NAME
POSIX - Perl interface to IEEE Std 1003.1
SYNOPSIS
use POSIX ();
use POSIX qw(setsid);
use POSIX qw(:errno_h :fcntl_h);
printf "EINTR is %d\n", EINTR;
$sess_id = POSIX::setsid();
$fd = POSIX::open($path, O_CREAT|O_EXCL|O_WRONLY, 0644);
# note: that's a filedescriptor, *NOT* a filehandle
DESCRIPTION
The POSIX module permits you to access all (or nearly all) the standard POSIX 1003.1 identifiers. Many of these identifiers have been given Perl-ish interfaces.
This document gives a condensed list of the features available in the POSIX module. Consult your operating system's manpages for general information on most features. Consult perlfunc for functions which are noted as being identical to Perl's builtin functions.
The first section describes POSIX functions from the 1003.1 specification. The second section describes some classes for signal objects, TTY objects, and other miscellaneous objects. The remaining sections list various constants and macros in an organization which roughly follows IEEE Std 1003.1b-1993.
CAVEATS
Everything is exported by default (with a handful of exceptions). This is an unfortunate backwards compatibility feature and its use is strongly discouraged. You should either prevent the exporting (by saying use POSIX ();
, as usual) and then use fully qualified names (e.g. POSIX::SEEK_END
), or give an explicit import list. If you do neither and opt for the default (as in use POSIX;
), you will import hundreds and hundreds of symbols into your namespace.
A few functions are not implemented because they are C specific. If you attempt to call these, they will print a message telling you that they aren't implemented, and suggest using the Perl equivalent, should one exist. For example, trying to access the setjmp()
call will elicit the message "setjmp() is C-specific: use eval {} instead
".
Furthermore, some evil vendors will claim 1003.1 compliance, but in fact are not so: they will not pass the PCTS (POSIX Compliance Test Suites). For example, one vendor may not define EDEADLK
, or the semantics of the errno values set by open(2)
might not be quite right. Perl does not attempt to verify POSIX compliance. That means you can currently successfully say "use POSIX", and then later in your program you find that your vendor has been lax and there's no usable ICANON
macro after all. This could be construed to be a bug.
FUNCTIONS
_exit
-
This is identical to the C function
_exit()
. It exits the program immediately which means among other things buffered I/O is not flushed.Note that when using threads and in Linux this is not a good way to exit a thread because in Linux processes and threads are kind of the same thing (Note: while this is the situation in early 2003 there are projects under way to have threads with more POSIXly semantics in Linux). If you want not to return from a thread, detach the thread.
abort
-
This is identical to the C function
abort()
. It terminates the process with aSIGABRT
signal unless caught by a signal handler or if the handler does not return normally (it e.g. does alongjmp
). abs
-
This is identical to Perl's builtin
abs()
function, returning the absolute value of its numerical argument. access
-
Determines the accessibility of a file.
if( POSIX::access( "/", &POSIX::R_OK ) ){ print "have read permission\n"; }
Returns
undef
on failure. Note: do not useaccess()
for security purposes. Between theaccess()
call and the operation you are preparing for the permissions might change: a classic race condition. acos
-
This is identical to the C function
acos()
, returning the arcus cosine of its numerical argument. See also Math::Trig. acosh
-
This is identical to the C function
acosh()
, returning the hyperbolic arcus cosine of its numerical argument [C99]. See also Math::Trig. alarm
-
This is identical to Perl's builtin
alarm()
function, either for arming or disarming theSIGARLM
timer. asctime
-
This is identical to the C function
asctime()
. It returns a string of the form"Fri Jun 2 18:22:13 2000\n\0"
and it is called thusly
$asctime = asctime($sec, $min, $hour, $mday, $mon, $year, $wday, $yday, $isdst);
The
$mon
is zero-based: January equals0
. The$year
is 1900-based: 2001 equals101
.$wday
and$yday
default to zero (and are usually ignored anyway), and$isdst
defaults to -1. asin
-
This is identical to the C function
asin()
, returning the arcus sine of its numerical argument. See also Math::Trig. asinh
-
This is identical to the C function
asinh()
, returning the hyperbolic arcus sine of its numerical argument [C99]. See also Math::Trig. assert
-
Unimplemented, but you can use "die" in perlfunc and the Carp module to achieve similar things.
atan
-
This is identical to the C function
atan()
, returning the arcus tangent of its numerical argument. See also Math::Trig. atanh
-
This is identical to the C function
atanh()
, returning the hyperbolic arcus tangent of its numerical argument [C99]. See also Math::Trig. atan2
-
This is identical to Perl's builtin
atan2()
function, returning the arcus tangent defined by its two numerical arguments, the y coordinate and the x coordinate. See also Math::Trig. atexit
-
Not implemented.
atexit()
is C-specific: useEND {}
instead, see perlmod. atof
-
Not implemented.
atof()
is C-specific. Perl converts strings to numbers transparently. If you need to force a scalar to a number, add a zero to it. atoi
-
Not implemented.
atoi()
is C-specific. Perl converts strings to numbers transparently. If you need to force a scalar to a number, add a zero to it. If you need to have just the integer part, see "int" in perlfunc. atol
-
Not implemented.
atol()
is C-specific. Perl converts strings to numbers transparently. If you need to force a scalar to a number, add a zero to it. If you need to have just the integer part, see "int" in perlfunc. bsearch
-
bsearch()
not supplied. For doing binary search on wordlists, see Search::Dict. calloc
-
Not implemented.
calloc()
is C-specific. Perl does memory management transparently. cbrt
-
The cube root [C99].
ceil
-
This is identical to the C function
ceil()
, returning the smallest integer value greater than or equal to the given numerical argument. chdir
-
This is identical to Perl's builtin
chdir()
function, allowing one to change the working (default) directory, see "chdir" in perlfunc. chmod
-
This is identical to Perl's builtin
chmod()
function, allowing one to change file and directory permissions, see "chmod" in perlfunc. chown
-
This is identical to Perl's builtin
chown()
function, allowing one to change file and directory owners and groups, see "chown" in perlfunc. clearerr
-
Not implemented. Use the method
IO::Handle::clearerr()
instead, to reset the error state (if any) and EOF state (if any) of the given stream. clock
-
This is identical to the C function
clock()
, returning the amount of spent processor time in microseconds. close
-
Close the file. This uses file descriptors such as those obtained by calling
POSIX::open
.$fd = POSIX::open( "foo", &POSIX::O_RDONLY ); POSIX::close( $fd );
Returns
undef
on failure.See also "close" in perlfunc.
closedir
-
This is identical to Perl's builtin
closedir()
function for closing a directory handle, see "closedir" in perlfunc. cos
-
This is identical to Perl's builtin
cos()
function, for returning the cosine of its numerical argument, see "cos" in perlfunc. See also Math::Trig. cosh
-
This is identical to the C function
cosh()
, for returning the hyperbolic cosine of its numeric argument. See also Math::Trig. copysign
-
Returns
x
but with the sign ofy
[C99].$x_with_sign_of_y = POSIX::copysign($x, $y);
See also "signbit".
creat
-
Create a new file. This returns a file descriptor like the ones returned by
POSIX::open
. UsePOSIX::close
to close the file.$fd = POSIX::creat( "foo", 0611 ); POSIX::close( $fd );
See also "sysopen" in perlfunc and its
O_CREAT
flag. ctermid
-
Generates the path name for the controlling terminal.
$path = POSIX::ctermid();
ctime
-
This is identical to the C function
ctime()
and equivalent toasctime(localtime(...))
, see "asctime" and "localtime". cuserid
-
Get the login name of the owner of the current process.
$name = POSIX::cuserid();
difftime
-
This is identical to the C function
difftime()
, for returning the time difference (in seconds) between two times (as returned bytime()
), see "time". div
-
Not implemented.
div()
is C-specific, use "int" in perlfunc on the usual/
division and the modulus%
. dup
-
This is similar to the C function
dup()
, for duplicating a file descriptor.This uses file descriptors such as those obtained by calling
POSIX::open
.Returns
undef
on failure. dup2
-
This is similar to the C function
dup2()
, for duplicating a file descriptor to an another known file descriptor.This uses file descriptors such as those obtained by calling
POSIX::open
.Returns
undef
on failure. erf
-
The error function [C99].
erfc
-
The complementary error function [C99].
errno
-
Returns the value of errno.
$errno = POSIX::errno();
This identical to the numerical values of the
$!
, see "$ERRNO" in perlvar. execl
-
Not implemented.
execl()
is C-specific, see "exec" in perlfunc. execle
-
Not implemented.
execle()
is C-specific, see "exec" in perlfunc. execlp
-
Not implemented.
execlp()
is C-specific, see "exec" in perlfunc. execv
-
Not implemented.
execv()
is C-specific, see "exec" in perlfunc. execve
-
Not implemented.
execve()
is C-specific, see "exec" in perlfunc. execvp
-
Not implemented.
execvp()
is C-specific, see "exec" in perlfunc. exit
-
This is identical to Perl's builtin
exit()
function for exiting the program, see "exit" in perlfunc. exp
-
This is identical to Perl's builtin
exp()
function for returning the exponent (e-based) of the numerical argument, see "exp" in perlfunc. expm1
-
Equivalent to
exp(x) - 1
, but more precise for small argument values [C99].See also "log1p".
fabs
-
This is identical to Perl's builtin
abs()
function for returning the absolute value of the numerical argument, see "abs" in perlfunc. fclose
-
Not implemented. Use method
IO::Handle::close()
instead, or see "close" in perlfunc. fcntl
-
This is identical to Perl's builtin
fcntl()
function, see "fcntl" in perlfunc. fdopen
-
Not implemented. Use method
IO::Handle::new_from_fd()
instead, or see "open" in perlfunc. feof
-
Not implemented. Use method
IO::Handle::eof()
instead, or see "eof" in perlfunc. ferror
-
Not implemented. Use method
IO::Handle::error()
instead. fflush
-
Not implemented. Use method
IO::Handle::flush()
instead. See also"$OUTPUT_AUTOFLUSH" in perlvar
. fgetc
-
Not implemented. Use method
IO::Handle::getc()
instead, or see "read" in perlfunc. fgetpos
-
Not implemented. Use method
IO::Seekable::getpos()
instead, or see "seek" in perlfunc. fgets
-
Not implemented. Use method
IO::Handle::gets()
instead. Similar to <>, also known as "readline" in perlfunc. fileno
-
Not implemented. Use method
IO::Handle::fileno()
instead, or see "fileno" in perlfunc. floor
-
This is identical to the C function
floor()
, returning the largest integer value less than or equal to the numerical argument. fdim
-
"Positive difference",
x - y
ifx > y
, zero otherwise [C99]. fegetround
-
Returns the current floating point rounding mode, one of
FE_TONEAREST FE_TOWARDZERO FE_UPWARD FE_UPWARD
FE_TONEAREST
is like "round",FE_TOWARDZERO
is like "trunc" [C99]. fesetround
-
Sets the floating point rounding mode, see "fegetround" [C99].
fma
-
"Fused multiply-add",
x * y + z
, possibly faster (and less lossy) than the explicit two operations [C99].my $fused = POSIX::fma($x, $y, $z);
fmax
-
Maximum of
x
andy
, except when either isNaN
, returns the other [C99].my $min = POSIX::fmax($x, $y);
fmin
-
Minimum of
x
andy
, except when either isNaN
, returns the other [C99].my $min = POSIX::fmin($x, $y);
fmod
-
This is identical to the C function
fmod()
.$r = fmod($x, $y);
It returns the remainder
$r = $x - $n*$y
, where$n = trunc($x/$y)
. The$r
has the same sign as$x
and magnitude (absolute value) less than the magnitude of$y
. fopen
-
Not implemented. Use method
IO::File::open()
instead, or see "open" in perlfunc. fork
-
This is identical to Perl's builtin
fork()
function for duplicating the current process, see "fork" in perlfunc and perlfork if you are in Windows. fpathconf
-
Retrieves the value of a configurable limit on a file or directory. This uses file descriptors such as those obtained by calling
POSIX::open
.The following will determine the maximum length of the longest allowable pathname on the filesystem which holds /var/foo.
$fd = POSIX::open( "/var/foo", &POSIX::O_RDONLY ); $path_max = POSIX::fpathconf($fd, &POSIX::_PC_PATH_MAX);
Returns
undef
on failure. fpclassify
-
Returns one of
FP_NORMAL FP_ZERO FP_SUBNORMAL FP_INFINITE FP_NAN
telling the class of the argument [C99].
FP_INFINITE
is positive or negative infinity,FP_NAN
is not-a-number.FP_SUBNORMAL
means subnormal numbers (also known as denormals), very small numbers with low precision.FP_ZERO
is zero.FP_NORMAL
is all the rest. fprintf
-
Not implemented.
fprintf()
is C-specific, see "printf" in perlfunc instead. fputc
-
Not implemented.
fputc()
is C-specific, see "print" in perlfunc instead. fputs
-
Not implemented.
fputs()
is C-specific, see "print" in perlfunc instead. fread
-
Not implemented.
fread()
is C-specific, see "read" in perlfunc instead. free
-
Not implemented.
free()
is C-specific. Perl does memory management transparently. freopen
-
Not implemented.
freopen()
is C-specific, see "open" in perlfunc instead. frexp
-
Return the mantissa and exponent of a floating-point number.
($mantissa, $exponent) = POSIX::frexp( 1.234e56 );
fscanf
-
Not implemented.
fscanf()
is C-specific, use <> and regular expressions instead. fseek
-
Not implemented. Use method
IO::Seekable::seek()
instead, or see "seek" in perlfunc. fsetpos
-
Not implemented. Use method
IO::Seekable::setpos()
instead, or seek "seek" in perlfunc. fstat
-
Get file status. This uses file descriptors such as those obtained by calling
POSIX::open
. The data returned is identical to the data from Perl's builtinstat
function.$fd = POSIX::open( "foo", &POSIX::O_RDONLY ); @stats = POSIX::fstat( $fd );
fsync
-
Not implemented. Use method
IO::Handle::sync()
instead. ftell
-
Not implemented. Use method
IO::Seekable::tell()
instead, or see "tell" in perlfunc. fwrite
-
Not implemented.
fwrite()
is C-specific, see "print" in perlfunc instead. getc
-
This is identical to Perl's builtin
getc()
function, see "getc" in perlfunc. getchar
-
Returns one character from STDIN. Identical to Perl's
getc()
, see "getc" in perlfunc. getcwd
-
Returns the name of the current working directory. See also Cwd.
getegid
-
Returns the effective group identifier. Similar to Perl' s builtin variable
$(
, see "$EGID" in perlvar. getenv
-
Returns the value of the specified environment variable. The same information is available through the
%ENV
array. geteuid
-
Returns the effective user identifier. Identical to Perl's builtin
$>
variable, see "$EUID" in perlvar. getgid
-
Returns the user's real group identifier. Similar to Perl's builtin variable
$)
, see "$GID" in perlvar. getgrgid
-
This is identical to Perl's builtin
getgrgid()
function for returning group entries by group identifiers, see "getgrgid" in perlfunc. getgrnam
-
This is identical to Perl's builtin
getgrnam()
function for returning group entries by group names, see "getgrnam" in perlfunc. getgroups
-
Returns the ids of the user's supplementary groups. Similar to Perl's builtin variable
$)
, see "$GID" in perlvar. getlogin
-
This is identical to Perl's builtin
getlogin()
function for returning the user name associated with the current session, see "getlogin" in perlfunc. getpayload
-
use POSIX ':nan_payload'; getpayload($var)
Returns the
NaN
payload.Note the API instability warning in "setpayload".
See "nan" for more discussion about
NaN
. getpgrp
-
This is identical to Perl's builtin
getpgrp()
function for returning the process group identifier of the current process, see "getpgrp" in perlfunc. getpid
-
Returns the process identifier. Identical to Perl's builtin variable
$$
, see "$PID" in perlvar. getppid
-
This is identical to Perl's builtin
getppid()
function for returning the process identifier of the parent process of the current process , see "getppid" in perlfunc. getpwnam
-
This is identical to Perl's builtin
getpwnam()
function for returning user entries by user names, see "getpwnam" in perlfunc. getpwuid
-
This is identical to Perl's builtin
getpwuid()
function for returning user entries by user identifiers, see "getpwuid" in perlfunc. gets
-
Returns one line from
STDIN
, similar to <>, also known as thereadline()
function, see "readline" in perlfunc.NOTE: if you have C programs that still use
gets()
, be very afraid. Thegets()
function is a source of endless grief because it has no buffer overrun checks. It should never be used. Thefgets()
function should be preferred instead. getuid
-
Returns the user's identifier. Identical to Perl's builtin
$<
variable, see "$UID" in perlvar. gmtime
-
This is identical to Perl's builtin
gmtime()
function for converting seconds since the epoch to a date in Greenwich Mean Time, see "gmtime" in perlfunc. hypot
-
Equivalent to
sqrt(x * x + y * y)
except more stable on very large or very small arguments [C99]. ilogb
-
Integer binary logarithm [C99]
For example
ilogb(20)
is 4, as an integer.See also "logb".
Inf
-
The infinity as a constant:
use POSIX qw(Inf); my $pos_inf = +Inf; # Or just Inf. my $neg_inf = -Inf;
See also "isinf", and "fpclassify".
isalnum
-
Deprecated function whose use raises a warning, and which is slated to be removed in a future Perl version. It is very similar to matching against
qr/ ^ [[:alnum:]]+ $ /x
, which you should convert to use instead. The function is deprecated because 1) it doesn't handle UTF-8 encoded strings properly; and 2) it returnsTRUE
even if the input is the empty string. The function return is always based on the current locale, whereas using locale rules is optional with the regular expression, based on pragmas in effect and pattern modifiers (see "Character set modifiers" in perlre and "Which character set modifier is in effect?" in perlre).The function returns
TRUE
if the input string is empty, or if the corresponding C function returnsTRUE
for every byte in the string.You may want to use the
/\w/
construct instead. isalpha
-
Deprecated function whose use raises a warning, and which is slated to be removed in a future Perl version. It is very similar to matching against
qr/ ^ [[:alpha:]]+ $ /x
, which you should convert to use instead. The function is deprecated because 1) it doesn't handle UTF-8 encoded strings properly; and 2) it returnsTRUE
even if the input is the empty string. The function return is always based on the current locale, whereas using locale rules is optional with the regular expression, based on pragmas in effect and pattern modifiers (see "Character set modifiers" in perlre and "Which character set modifier is in effect?" in perlre).The function returns
TRUE
if the input string is empty, or if the corresponding C function returnsTRUE
for every byte in the string. isatty
-
Returns a boolean indicating whether the specified filehandle is connected to a tty. Similar to the
-t
operator, see "-X" in perlfunc. iscntrl
-
Deprecated function whose use raises a warning, and which is slated to be removed in a future Perl version. It is very similar to matching against
qr/ ^ [[:cntrl:]]+ $ /x
, which you should convert to use instead. The function is deprecated because 1) it doesn't handle UTF-8 encoded strings properly; and 2) it returnsTRUE
even if the input is the empty string. The function return is always based on the current locale, whereas using locale rules is optional with the regular expression, based on pragmas in effect and pattern modifiers (see "Character set modifiers" in perlre and "Which character set modifier is in effect?" in perlre).The function returns
TRUE
if the input string is empty, or if the corresponding C function returnsTRUE
for every byte in the string. isdigit
-
Deprecated function whose use raises a warning, and which is slated to be removed in a future Perl version. It is very similar to matching against
qr/ ^ [[:digit:]]+ $ /x
, which you should convert to use instead. The function is deprecated because 1) it doesn't handle UTF-8 encoded strings properly; and 2) it returnsTRUE
even if the input is the empty string. The function return is always based on the current locale, whereas using locale rules is optional with the regular expression, based on pragmas in effect and pattern modifiers (see "Character set modifiers" in perlre and "Which character set modifier is in effect?" in perlre).The function returns
TRUE
if the input string is empty, or if the corresponding C function returnsTRUE
for every byte in the string.You may want to use the
/\d/
construct instead. isfinite
-
Returns true if the argument is a finite number (that is, not an infinity, or the not-a-number) [C99].
See also "isinf", "isnan", and "fpclassify".
isgraph
-
Deprecated function whose use raises a warning, and which is slated to be removed in a future Perl version. It is very similar to matching against
qr/ ^ [[:graph:]]+ $ /x
, which you should convert to use instead. The function is deprecated because 1) it doesn't handle UTF-8 encoded strings properly; and 2) it returnsTRUE
even if the input is the empty string. The function return is always based on the current locale, whereas using locale rules is optional with the regular expression, based on pragmas in effect and pattern modifiers (see "Character set modifiers" in perlre and "Which character set modifier is in effect?" in perlre).The function returns
TRUE
if the input string is empty, or if the corresponding C function returnsTRUE
for every byte in the string. isgreater
-
(Also
isgreaterequal
,isless
,islessequal
,islessgreater
,isunordered
)Floating point comparisons which handle the
NaN
[C99]. isinf
-
Returns true if the argument is an infinity (positive or negative) [C99].
See also "Inf", "isnan", "isfinite", and "fpclassify".
islower
-
Deprecated function whose use raises a warning, and which is slated to be removed in a future Perl version. It is very similar to matching against
qr/ ^ [[:lower:]]+ $ /x
, which you should convert to use instead. The function is deprecated because 1) it doesn't handle UTF-8 encoded strings properly; and 2) it returnsTRUE
even if the input is the empty string. The function return is always based on the current locale, whereas using locale rules is optional with the regular expression, based on pragmas in effect and pattern modifiers (see "Character set modifiers" in perlre and "Which character set modifier is in effect?" in perlre).The function returns
TRUE
if the input string is empty, or if the corresponding C function returnsTRUE
for every byte in the string.Do not use
/[a-z]/
unless you don't care about the current locale. isnan
-
Returns true if the argument is
NaN
(not-a-number) [C99].Note that you cannot test for "
NaN
-ness" with$x == $x
since the
NaN
is not equivalent to anything, including itself.See also "nan", "NaN", "isinf", and "fpclassify".
isnormal
-
Returns true if the argument is normal (that is, not a subnormal/denormal, and not an infinity, or a not-a-number) [C99].
See also "isfinite", and "fpclassify".
isprint
-
Deprecated function whose use raises a warning, and which is slated to be removed in a future Perl version. It is very similar to matching against
qr/ ^ [[:print:]]+ $ /x
, which you should convert to use instead. The function is deprecated because 1) it doesn't handle UTF-8 encoded strings properly; and 2) it returnsTRUE
even if the input is the empty string. The function return is always based on the current locale, whereas using locale rules is optional with the regular expression, based on pragmas in effect and pattern modifiers (see "Character set modifiers" in perlre and "Which character set modifier is in effect?" in perlre).The function returns
TRUE
if the input string is empty, or if the corresponding C function returnsTRUE
for every byte in the string. ispunct
-
Deprecated function whose use raises a warning, and which is slated to be removed in a future Perl version. It is very similar to matching against
qr/ ^ [[:punct:]]+ $ /x
, which you should convert to use instead. The function is deprecated because 1) it doesn't handle UTF-8 encoded strings properly; and 2) it returnsTRUE
even if the input is the empty string. The function return is always based on the current locale, whereas using locale rules is optional with the regular expression, based on pragmas in effect and pattern modifiers (see "Character set modifiers" in perlre and "Which character set modifier is in effect?" in perlre).The function returns
TRUE
if the input string is empty, or if the corresponding C function returnsTRUE
for every byte in the string. issignaling
-
use POSIX ':nan_payload'; issignaling($var, $payload)
Return true if the argument is a signaling NaN.
Note the API instability warning in "setpayload".
See "nan" for more discussion about
NaN
. isspace
-
Deprecated function whose use raises a warning, and which is slated to be removed in a future Perl version. It is very similar to matching against
qr/ ^ [[:space:]]+ $ /x
, which you should convert to use instead. The function is deprecated because 1) it doesn't handle UTF-8 encoded strings properly; and 2) it returnsTRUE
even if the input is the empty string. The function return is always based on the current locale, whereas using locale rules is optional with the regular expression, based on pragmas in effect and pattern modifiers (see "Character set modifiers" in perlre and "Which character set modifier is in effect?" in perlre).The function returns
TRUE
if the input string is empty, or if the corresponding C function returnsTRUE
for every byte in the string.You may want to use the
/\s/
construct instead. isupper
-
Deprecated function whose use raises a warning, and which is slated to be removed in a future Perl version. It is very similar to matching against
qr/ ^ [[:upper:]]+ $ /x
, which you should convert to use instead. The function is deprecated because 1) it doesn't handle UTF-8 encoded strings properly; and 2) it returnsTRUE
even if the input is the empty string. The function return is always based on the current locale, whereas using locale rules is optional with the regular expression, based on pragmas in effect and pattern modifiers (see "Character set modifiers" in perlre and "Which character set modifier is in effect?" in perlre).The function returns
TRUE
if the input string is empty, or if the corresponding C function returnsTRUE
for every byte in the string.Do not use
/[A-Z]/
unless you don't care about the current locale. isxdigit
-
Deprecated function whose use raises a warning, and which is slated to be removed in a future Perl version. It is very similar to matching against
qr/ ^ [[:xdigit:]]+ $ /x
, which you should convert to use instead. The function is deprecated because 1) it doesn't handle UTF-8 encoded strings properly; and 2) it returnsTRUE
even if the input is the empty string. The function return is always based on the current locale, whereas using locale rules is optional with the regular expression, based on pragmas in effect and pattern modifiers (see "Character set modifiers" in perlre and "Which character set modifier is in effect?" in perlre).The function returns
TRUE
if the input string is empty, or if the corresponding C function returnsTRUE
for every byte in the string. j0
j1
jn
y0
y1
yn
-
The Bessel function of the first kind of the order zero.
kill
-
This is identical to Perl's builtin
kill()
function for sending signals to processes (often to terminate them), see "kill" in perlfunc. labs
-
Not implemented. (For returning absolute values of long integers.)
labs()
is C-specific, see "abs" in perlfunc instead. lchown
-
This is identical to the C function, except the order of arguments is consistent with Perl's builtin
chown()
with the added restriction of only one path, not a list of paths. Does the same thing as thechown()
function but changes the owner of a symbolic link instead of the file the symbolic link points to.POSIX::lchown($uid, $gid, $file_path);
ldexp
-
This is identical to the C function
ldexp()
for multiplying floating point numbers with powers of two.$x_quadrupled = POSIX::ldexp($x, 2);
ldiv
-
Not implemented. (For computing dividends of long integers.)
ldiv()
is C-specific, use/
andint()
instead. lgamma
-
The logarithm of the Gamma function [C99].
See also "tgamma".
log1p
-
Equivalent to
log(1 + x)
, but more stable results for small argument values [C99]. log2
-
Logarithm base two [C99].
See also "expm1".
logb
-
Integer binary logarithm [C99].
For example
logb(20)
is 4, as a floating point number.See also "ilogb".
link
-
This is identical to Perl's builtin
link()
function for creating hard links into files, see "link" in perlfunc. localeconv
-
Get numeric formatting information. Returns a reference to a hash containing the current underlying locale's formatting values. Users of this function should also read perllocale, which provides a comprehensive discussion of Perl locale handling, including a section devoted to this function.
Here is how to query the database for the de (Deutsch or German) locale.
my $loc = POSIX::setlocale( &POSIX::LC_ALL, "de" ); print "Locale: \"$loc\"\n"; my $lconv = POSIX::localeconv(); foreach my $property (qw( decimal_point thousands_sep grouping int_curr_symbol currency_symbol mon_decimal_point mon_thousands_sep mon_grouping positive_sign negative_sign int_frac_digits frac_digits p_cs_precedes p_sep_by_space n_cs_precedes n_sep_by_space p_sign_posn n_sign_posn int_p_cs_precedes int_p_sep_by_space int_n_cs_precedes int_n_sep_by_space int_p_sign_posn int_n_sign_posn )) { printf qq(%s: "%s",\n), $property, $lconv->{$property}; }
The members whose names begin with
int_p_
andint_n_
were added by POSIX.1-2008 and are only available on systems that support them. localtime
-
This is identical to Perl's builtin
localtime()
function for converting seconds since the epoch to a date see "localtime" in perlfunc. log
-
This is identical to Perl's builtin
log()
function, returning the natural (e-based) logarithm of the numerical argument, see "log" in perlfunc. log10
-
This is identical to the C function
log10()
, returning the 10-base logarithm of the numerical argument. You can also usesub log10 { log($_[0]) / log(10) }
or
sub log10 { log($_[0]) / 2.30258509299405 }
or
sub log10 { log($_[0]) * 0.434294481903252 }
longjmp
-
Not implemented.
longjmp()
is C-specific: use "die" in perlfunc instead. lseek
-
Move the file's read/write position. This uses file descriptors such as those obtained by calling
POSIX::open
.$fd = POSIX::open( "foo", &POSIX::O_RDONLY ); $off_t = POSIX::lseek( $fd, 0, &POSIX::SEEK_SET );
Returns
undef
on failure. lrint
-
Depending on the current floating point rounding mode, rounds the argument either toward nearest (like "round"), toward zero (like "trunc"), downward (toward negative infinity), or upward (toward positive infinity) [C99].
For the rounding mode, see "fegetround".
lround
-
Like "round", but as integer, as opposed to floating point [C99].
malloc
-
Not implemented.
malloc()
is C-specific. Perl does memory management transparently. mblen
-
This is identical to the C function
mblen()
.Core Perl does not have any support for the wide and multibyte characters of the C standards, except under UTF-8 locales, so this might be a rather useless function.
However, Perl supports Unicode, see perluniintro.
mbstowcs
-
This is identical to the C function
mbstowcs()
.See "mblen".
mbtowc
-
This is identical to the C function
mbtowc()
.See "mblen".
memchr
-
Not implemented.
memchr()
is C-specific, see "index" in perlfunc instead. memcmp
-
Not implemented.
memcmp()
is C-specific, useeq
instead, see perlop. memcpy
-
Not implemented.
memcpy()
is C-specific, use=
, see perlop, or see "substr" in perlfunc. memmove
-
Not implemented.
memmove()
is C-specific, use=
, see perlop, or see "substr" in perlfunc. memset
-
Not implemented.
memset()
is C-specific, usex
instead, see perlop. mkdir
-
This is identical to Perl's builtin
mkdir()
function for creating directories, see "mkdir" in perlfunc. mkfifo
-
This is similar to the C function
mkfifo()
for creating FIFO special files.if (mkfifo($path, $mode)) { ....
Returns
undef
on failure. The$mode
is similar to the mode ofmkdir()
, see "mkdir" in perlfunc, though formkfifo
you must specify the$mode
. mktime
-
Convert date/time info to a calendar time.
Synopsis:
mktime(sec, min, hour, mday, mon, year, wday = 0, yday = 0, isdst = -1)
The month (
mon
), weekday (wday
), and yearday (yday
) begin at zero, i.e., January is 0, not 1; Sunday is 0, not 1; January 1st is 0, not 1. The year (year
) is given in years since 1900; i.e., the year 1995 is 95; the year 2001 is 101. Consult your system'smktime()
manpage for details about these and the other arguments.Calendar time for December 12, 1995, at 10:30 am.
$time_t = POSIX::mktime( 0, 30, 10, 12, 11, 95 ); print "Date = ", POSIX::ctime($time_t);
Returns
undef
on failure. modf
-
Return the integral and fractional parts of a floating-point number.
($fractional, $integral) = POSIX::modf( 3.14 );
See also "round".
NaN
-
The not-a-number as a constant:
use POSIX qw(NaN); my $nan = NaN;
See also "nan",
/isnan
, and "fpclassify". nan
-
my $nan = nan();
Returns
NaN
, not-a-number [C99].The returned NaN is always a quiet NaN, as opposed to signaling.
With an argument, can be used to generate a NaN with payload. The argument is first interpreted as a floating point number, but then any fractional parts are truncated (towards zero), and the value is interpreted as an unsigned integer. The bits of this integer are stored in the unused bits of the NaN.
The result has a dual nature: it is a NaN, but it also carries the integer inside it. The integer can be retrieved with "getpayload". Note, though, that the payload is not propagated, not even on copies, and definitely not in arithmetic operations.
How many bits fit in the NaN depends on what kind of floating points are being used, but on the most common platforms (64-bit IEEE 754, or the x86 80-bit long doubles) there are 51 and 61 bits available, respectively. (There would be 52 and 62, but the quiet/signaling bit of NaNs takes away one.) However, because of the floating-point-to- integer-and-back conversions, please test carefully whether you get back what you put in. If your integers are only 32 bits wide, you probably should not rely on more than 32 bits of payload.
Whether a "signaling" NaN is in any way different from a "quiet" NaN, depends on the platform. Also note that the payload of the default NaN (no argument to nan()) is not necessarily zero, use
setpayload
to explicitly set the payload. On some platforms like the 32-bit x86, (unless using the 80-bit long doubles) the signaling bit is not supported at all.See also "isnan", "NaN", "setpayload" and "issignaling".
nearbyint
-
Returns the nearest integer to the argument, according to the current rounding mode (see "fegetround") [C99].
nextafter
-
Returns the next representable floating point number after
x
in the direction ofy
[C99].my $nextafter = POSIX::nextafter($x, $y);
Like "nexttoward", but potentially less accurate.
nexttoward
-
Returns the next representable floating point number after
x
in the direction ofy
[C99].my $nexttoward = POSIX::nexttoward($x, $y);
Like "nextafter", but potentially more accurate.
nice
-
This is similar to the C function
nice()
, for changing the scheduling preference of the current process. Positive arguments mean a more polite process, negative values a more needy process. Normal (non-root) user processes can only change towards being more polite.Returns
undef
on failure. offsetof
-
Not implemented.
offsetof()
is C-specific, you probably want to see "pack" in perlfunc instead. open
-
Open a file for reading for writing. This returns file descriptors, not Perl filehandles. Use
POSIX::close
to close the file.Open a file read-only with mode 0666.
$fd = POSIX::open( "foo" );
Open a file for read and write.
$fd = POSIX::open( "foo", &POSIX::O_RDWR );
Open a file for write, with truncation.
$fd = POSIX::open( "foo", &POSIX::O_WRONLY | &POSIX::O_TRUNC );
Create a new file with mode 0640. Set up the file for writing.
$fd = POSIX::open( "foo", &POSIX::O_CREAT | &POSIX::O_WRONLY, 0640 );
Returns
undef
on failure.See also "sysopen" in perlfunc.
opendir
-
Open a directory for reading.
$dir = POSIX::opendir( "/var" ); @files = POSIX::readdir( $dir ); POSIX::closedir( $dir );
Returns
undef
on failure. pathconf
-
Retrieves the value of a configurable limit on a file or directory.
The following will determine the maximum length of the longest allowable pathname on the filesystem which holds
/var
.$path_max = POSIX::pathconf( "/var", &POSIX::_PC_PATH_MAX );
Returns
undef
on failure. pause
-
This is similar to the C function
pause()
, which suspends the execution of the current process until a signal is received.Returns
undef
on failure. perror
-
This is identical to the C function
perror()
, which outputs to the standard error stream the specified message followed by": "
and the current error string. Use thewarn()
function and the$!
variable instead, see "warn" in perlfunc and "$ERRNO" in perlvar. pipe
-
Create an interprocess channel. This returns file descriptors like those returned by
POSIX::open
.my ($read, $write) = POSIX::pipe(); POSIX::write( $write, "hello", 5 ); POSIX::read( $read, $buf, 5 );
See also "pipe" in perlfunc.
pow
-
Computes
$x
raised to the power$exponent
.$ret = POSIX::pow( $x, $exponent );
You can also use the
**
operator, see perlop. printf
-
Formats and prints the specified arguments to
STDOUT
. See also "printf" in perlfunc. putc
-
Not implemented.
putc()
is C-specific, see "print" in perlfunc instead. putchar
-
Not implemented.
putchar()
is C-specific, see "print" in perlfunc instead. puts
-
Not implemented.
puts()
is C-specific, see "print" in perlfunc instead. qsort
-
Not implemented.
qsort()
is C-specific, see "sort" in perlfunc instead. raise
-
Sends the specified signal to the current process. See also "kill" in perlfunc and the
$$
in "$PID" in perlvar. rand
-
Not implemented.
rand()
is non-portable, see "rand" in perlfunc instead. read
-
Read from a file. This uses file descriptors such as those obtained by calling
POSIX::open
. If the buffer$buf
is not large enough for the read then Perl will extend it to make room for the request.$fd = POSIX::open( "foo", &POSIX::O_RDONLY ); $bytes = POSIX::read( $fd, $buf, 3 );
Returns
undef
on failure.See also "sysread" in perlfunc.
readdir
-
This is identical to Perl's builtin
readdir()
function for reading directory entries, see "readdir" in perlfunc. realloc
-
Not implemented.
realloc()
is C-specific. Perl does memory management transparently. remainder
-
Given
x
andy
, returns the valuex - n*y
, wheren
is the integer closest tox
/y
. [C99]my $remainder = POSIX::remainder($x, $y)
See also "remquo".
remove
-
This is identical to Perl's builtin
unlink()
function for removing files, see "unlink" in perlfunc. remquo
-
Like "remainder" but also returns the low-order bits of the quotient (n) [C99]
(This is quite esoteric interface, mainly used to implement numerical algorithms.)
rename
-
This is identical to Perl's builtin
rename()
function for renaming files, see "rename" in perlfunc. rewind
-
Seeks to the beginning of the file.
rewinddir
-
This is identical to Perl's builtin
rewinddir()
function for rewinding directory entry streams, see "rewinddir" in perlfunc. rint
-
Identical to "lrint".
rmdir
-
This is identical to Perl's builtin
rmdir()
function for removing (empty) directories, see "rmdir" in perlfunc. round
-
Returns the integer (but still as floating point) nearest to the argument [C99].
scalbn
-
Returns
x * 2**y
[C99]. scanf
-
Not implemented.
scanf()
is C-specific, use <> and regular expressions instead, see perlre. setgid
-
Sets the real group identifier and the effective group identifier for this process. Similar to assigning a value to the Perl's builtin
$)
variable, see "$EGID" in perlvar, except that the latter will change only the real user identifier, and that the setgid() uses only a single numeric argument, as opposed to a space-separated list of numbers. setjmp
-
Not implemented.
setjmp()
is C-specific: useeval {}
instead, see "eval" in perlfunc. setlocale
-
Modifies and queries the program's underlying locale. Users of this function should read perllocale, whch provides a comprehensive discussion of Perl locale handling, knowledge of which is necessary to properly use this function. It contains a section devoted to this function. The discussion here is merely a summary reference for
setlocale()
. Note that Perl itself is almost entirely unaffected by the locale except within the scope of"use locale"
. (Exceptions are listed in "Not within the scope of "use locale"" in perllocale.)The following examples assume
use POSIX qw(setlocale LC_ALL LC_CTYPE);
has been issued.
The following will set the traditional UNIX system locale behavior (the second argument
"C"
).$loc = setlocale( LC_ALL, "C" );
The following will query the current
LC_CTYPE
category. (No second argument means 'query'.)$loc = setlocale( LC_CTYPE );
The following will set the
LC_CTYPE
behaviour according to the locale environment variables (the second argument""
). Please see your system'ssetlocale(3)
documentation for the locale environment variables' meaning or consult perllocale.$loc = setlocale( LC_CTYPE, "" );
The following will set the
LC_COLLATE
behaviour to Argentinian Spanish. NOTE: The naming and availability of locales depends on your operating system. Please consult perllocale for how to find out which locales are available in your system.$loc = setlocale( LC_COLLATE, "es_AR.ISO8859-1" );
setpayload
-
use POSIX ':nan_payload'; setpayload($var, $payload);
Sets the
NaN
payload of var.NOTE: the NaN payload APIs are based on the latest (as of June 2015) proposed ISO C interfaces, but they are not yet a standard. Things may change.
See "nan" for more discussion about
NaN
.See also "setpayloadsig", "isnan", "getpayload", and "issignaling".
setpayloadsig
-
use POSIX ':nan_payload'; setpayloadsig($var, $payload);
Like "setpayload" but also makes the NaN signaling.
Depending on the platform the NaN may or may not behave differently.
Note the API instability warning in "setpayload".
Note that because how the floating point formats work out, on the most common platforms signaling payload of zero is best avoided, since it might end up being identical to
+Inf
.See also "nan", "isnan", "getpayload", and "issignaling".
setpgid
-
This is similar to the C function
setpgid()
for setting the process group identifier of the current process.Returns
undef
on failure. setsid
-
This is identical to the C function
setsid()
for setting the session identifier of the current process. setuid
-
Sets the real user identifier and the effective user identifier for this process. Similar to assigning a value to the Perl's builtin
$<
variable, see "$UID" in perlvar, except that the latter will change only the real user identifier. sigaction
-
Detailed signal management. This uses
POSIX::SigAction
objects for theaction
andoldaction
arguments (the oldaction can also be just a hash reference). Consult your system'ssigaction
manpage for details, see alsoPOSIX::SigRt
.Synopsis:
sigaction(signal, action, oldaction = 0)
Returns
undef
on failure. Thesignal
must be a number (likeSIGHUP
), not a string (like"SIGHUP"
), though Perl does try hard to understand you.If you use the
SA_SIGINFO
flag, the signal handler will in addition to the first argument, the signal name, also receive a second argument, a hash reference, inside which are the following keys with the following semantics, as defined by POSIX/SUSv3:signo the signal number errno the error number code if this is zero or less, the signal was sent by a user process and the uid and pid make sense, otherwise the signal was sent by the kernel
The following are also defined by POSIX/SUSv3, but unfortunately not very widely implemented:
pid the process id generating the signal uid the uid of the process id generating the signal status exit value or signal for SIGCHLD band band event for SIGPOLL
A third argument is also passed to the handler, which contains a copy of the raw binary contents of the
siginfo
structure: if a system has some non-POSIX fields, this third argument is where tounpack()
them from.Note that not all
siginfo
values make sense simultaneously (some are valid only for certain signals, for example), and not all values make sense from Perl perspective, you should to consult your system'ssigaction
and possibly alsosiginfo
documentation. siglongjmp
-
Not implemented.
siglongjmp()
is C-specific: use "die" in perlfunc instead. signbit
-
Returns zero for positive arguments, non-zero for negative arguments [C99].
sigpending
-
Examine signals that are blocked and pending. This uses
POSIX::SigSet
objects for thesigset
argument. Consult your system'ssigpending
manpage for details.Synopsis:
sigpending(sigset)
Returns
undef
on failure. sigprocmask
-
Change and/or examine calling process's signal mask. This uses
POSIX::SigSet
objects for thesigset
andoldsigset
arguments. Consult your system'ssigprocmask
manpage for details.Synopsis:
sigprocmask(how, sigset, oldsigset = 0)
Returns
undef
on failure.Note that you can't reliably block or unblock a signal from its own signal handler if you're using safe signals. Other signals can be blocked or unblocked reliably.
sigsetjmp
-
Not implemented.
sigsetjmp()
is C-specific: useeval {}
instead, see "eval" in perlfunc. sigsuspend
-
Install a signal mask and suspend process until signal arrives. This uses
POSIX::SigSet
objects for thesignal_mask
argument. Consult your system'ssigsuspend
manpage for details.Synopsis:
sigsuspend(signal_mask)
Returns
undef
on failure. sin
-
This is identical to Perl's builtin
sin()
function for returning the sine of the numerical argument, see "sin" in perlfunc. See also Math::Trig. sinh
-
This is identical to the C function
sinh()
for returning the hyperbolic sine of the numerical argument. See also Math::Trig. sleep
-
This is functionally identical to Perl's builtin
sleep()
function for suspending the execution of the current for process for certain number of seconds, see "sleep" in perlfunc. There is one significant difference, however:POSIX::sleep()
returns the number of unslept seconds, while theCORE::sleep()
returns the number of slept seconds. sprintf
-
This is similar to Perl's builtin
sprintf()
function for returning a string that has the arguments formatted as requested, see "sprintf" in perlfunc. sqrt
-
This is identical to Perl's builtin
sqrt()
function. for returning the square root of the numerical argument, see "sqrt" in perlfunc. srand
-
Give a seed the pseudorandom number generator, see "srand" in perlfunc.
sscanf
-
Not implemented.
sscanf()
is C-specific, use regular expressions instead, see perlre. stat
-
This is identical to Perl's builtin
stat()
function for returning information about files and directories. strcat
-
Not implemented.
strcat()
is C-specific, use.=
instead, see perlop. strchr
-
Not implemented.
strchr()
is C-specific, see "index" in perlfunc instead. strcmp
-
Not implemented.
strcmp()
is C-specific, useeq
orcmp
instead, see perlop. strcoll
-
This is identical to the C function
strcoll()
for collating (comparing) strings transformed using thestrxfrm()
function. Not really needed since Perl can do this transparently, see perllocale. strcpy
-
Not implemented.
strcpy()
is C-specific, use=
instead, see perlop. strcspn
-
Not implemented.
strcspn()
is C-specific, use regular expressions instead, see perlre. strerror
-
Returns the error string for the specified errno. Identical to the string form of
$!
, see "$ERRNO" in perlvar. strftime
-
Convert date and time information to string. Returns the string.
Synopsis:
strftime(fmt, sec, min, hour, mday, mon, year, wday = -1, yday = -1, isdst = -1)
The month (
mon
), weekday (wday
), and yearday (yday
) begin at zero, i.e., January is 0, not 1; Sunday is 0, not 1; January 1st is 0, not 1. The year (year
) is given in years since 1900, i.e., the year 1995 is 95; the year 2001 is 101. Consult your system'sstrftime()
manpage for details about these and the other arguments.If you want your code to be portable, your format (
fmt
) argument should use only the conversion specifiers defined by the ANSI C standard (C89, to play safe). These areaAbBcdHIjmMpSUwWxXyYZ%
. But even then, the results of some of the conversion specifiers are non-portable. For example, the specifiersaAbBcpZ
change according to the locale settings of the user, and both how to set locales (the locale names) and what output to expect are non-standard. The specifierc
changes according to the timezone settings of the user and the timezone computation rules of the operating system. TheZ
specifier is notoriously unportable since the names of timezones are non-standard. Sticking to the numeric specifiers is the safest route.The given arguments are made consistent as though by calling
mktime()
before calling your system'sstrftime()
function, except that theisdst
value is not affected.The string for Tuesday, December 12, 1995.
$str = POSIX::strftime( "%A, %B %d, %Y", 0, 0, 0, 12, 11, 95, 2 ); print "$str\n";
strlen
-
Not implemented.
strlen()
is C-specific, uselength()
instead, see "length" in perlfunc. strncat
-
Not implemented.
strncat()
is C-specific, use.=
instead, see perlop. strncmp
-
Not implemented.
strncmp()
is C-specific, useeq
instead, see perlop. strncpy
-
Not implemented.
strncpy()
is C-specific, use=
instead, see perlop. strpbrk
-
Not implemented.
strpbrk()
is C-specific, use regular expressions instead, see perlre. strrchr
-
Not implemented.
strrchr()
is C-specific, see "rindex" in perlfunc instead. strspn
-
Not implemented.
strspn()
is C-specific, use regular expressions instead, see perlre. strstr
-
This is identical to Perl's builtin
index()
function, see "index" in perlfunc. strtod
-
String to double translation. Returns the parsed number and the number of characters in the unparsed portion of the string. Truly POSIX-compliant systems set
$!
($ERRNO
) to indicate a translation error, so clear$!
before callingstrtod
. However, non-POSIX systems may not check for overflow, and therefore will never set$!
.strtod
respects any POSIXsetlocale()
LC_TIME
settings, regardless of whether or not it is called from Perl code that is within the scope ofuse locale
.To parse a string
$str
as a floating point number use$! = 0; ($num, $n_unparsed) = POSIX::strtod($str);
The second returned item and
$!
can be used to check for valid input:if (($str eq '') || ($n_unparsed != 0) || $!) { die "Non-numeric input $str" . ($! ? ": $!\n" : "\n"); }
When called in a scalar context
strtod
returns the parsed number. strtok
-
Not implemented.
strtok()
is C-specific, use regular expressions instead, see perlre, or "split" in perlfunc. strtol
-
String to (long) integer translation. Returns the parsed number and the number of characters in the unparsed portion of the string. Truly POSIX-compliant systems set
$!
($ERRNO
) to indicate a translation error, so clear$!
before callingstrtol
. However, non-POSIX systems may not check for overflow, and therefore will never set$!
.strtol
should respect any POSIX setlocale() settings.To parse a string
$str
as a number in some base$base
use$! = 0; ($num, $n_unparsed) = POSIX::strtol($str, $base);
The base should be zero or between 2 and 36, inclusive. When the base is zero or omitted
strtol
will use the string itself to determine the base: a leading "0x" or "0X" means hexadecimal; a leading "0" means octal; any other leading characters mean decimal. Thus, "1234" is parsed as a decimal number, "01234" as an octal number, and "0x1234" as a hexadecimal number.The second returned item and
$!
can be used to check for valid input:if (($str eq '') || ($n_unparsed != 0) || !$!) { die "Non-numeric input $str" . $! ? ": $!\n" : "\n"; }
When called in a scalar context
strtol
returns the parsed number. strtold
-
Like "strtod" but for long doubles. Defined only if the system supports long doubles.
strtoul
-
String to unsigned (long) integer translation.
strtoul()
is identical tostrtol()
except thatstrtoul()
only parses unsigned integers. See "strtol" for details.Note: Some vendors supply
strtod()
andstrtol()
but notstrtoul()
. Other vendors that do supplystrtoul()
parse "-1" as a valid value. strxfrm
-
String transformation. Returns the transformed string.
$dst = POSIX::strxfrm( $src );
Used in conjunction with the
strcoll()
function, see "strcoll".Not really needed since Perl can do this transparently, see perllocale.
sysconf
-
Retrieves values of system configurable variables.
The following will get the machine's clock speed.
$clock_ticks = POSIX::sysconf( &POSIX::_SC_CLK_TCK );
Returns
undef
on failure. system
-
This is identical to Perl's builtin
system()
function, see "system" in perlfunc. tan
-
This is identical to the C function
tan()
, returning the tangent of the numerical argument. See also Math::Trig. tanh
-
This is identical to the C function
tanh()
, returning the hyperbolic tangent of the numerical argument. See also Math::Trig. tcdrain
-
This is similar to the C function
tcdrain()
for draining the output queue of its argument stream.Returns
undef
on failure. tcflow
-
This is similar to the C function
tcflow()
for controlling the flow of its argument stream.Returns
undef
on failure. tcflush
-
This is similar to the C function
tcflush()
for flushing the I/O buffers of its argument stream.Returns
undef
on failure. tcgetpgrp
-
This is identical to the C function
tcgetpgrp()
for returning the process group identifier of the foreground process group of the controlling terminal. tcsendbreak
-
This is similar to the C function
tcsendbreak()
for sending a break on its argument stream.Returns
undef
on failure. tcsetpgrp
-
This is similar to the C function
tcsetpgrp()
for setting the process group identifier of the foreground process group of the controlling terminal.Returns
undef
on failure. tgamma
-
The Gamma function [C99].
See also "lgamma".
time
-
This is identical to Perl's builtin
time()
function for returning the number of seconds since the epoch (whatever it is for the system), see "time" in perlfunc. times
-
The
times()
function returns elapsed realtime since some point in the past (such as system startup), user and system times for this process, and user and system times used by child processes. All times are returned in clock ticks.($realtime, $user, $system, $cuser, $csystem) = POSIX::times();
Note: Perl's builtin
times()
function returns four values, measured in seconds. tmpfile
-
Not implemented. Use method
IO::File::new_tmpfile()
instead, or see File::Temp. tmpnam
-
Returns a name for a temporary file.
$tmpfile = POSIX::tmpnam();
For security reasons, which are probably detailed in your system's documentation for the C library
tmpnam()
function, this interface should not be used; instead see File::Temp. tolower
-
This is identical to the C function, except that it can apply to a single character or to a whole string, and currently operates as if the locale always is "C". Consider using the
lc()
function, see "lc" in perlfunc, see "lc" in perlfunc, or the equivalent\L
operator inside doublequotish strings. toupper
-
This is similar to the C function, except that it can apply to a single character or to a whole string, and currently operates as if the locale always is "C". Consider using the
uc()
function, see "uc" in perlfunc, or the equivalent\U
operator inside doublequotish strings. trunc
-
Returns the integer toward zero from the argument [C99].
ttyname
-
This is identical to the C function
ttyname()
for returning the name of the current terminal. tzname
-
Retrieves the time conversion information from the
tzname
variable.POSIX::tzset(); ($std, $dst) = POSIX::tzname();
tzset
-
This is identical to the C function
tzset()
for setting the current timezone based on the environment variableTZ
, to be used byctime()
,localtime()
,mktime()
, andstrftime()
functions. umask
-
This is identical to Perl's builtin
umask()
function for setting (and querying) the file creation permission mask, see "umask" in perlfunc. uname
-
Get name of current operating system.
($sysname, $nodename, $release, $version, $machine) = POSIX::uname();
Note that the actual meanings of the various fields are not that well standardized, do not expect any great portability. The
$sysname
might be the name of the operating system, the$nodename
might be the name of the host, the$release
might be the (major) release number of the operating system, the$version
might be the (minor) release number of the operating system, and the$machine
might be a hardware identifier. Maybe. ungetc
-
Not implemented. Use method
IO::Handle::ungetc()
instead. unlink
-
This is identical to Perl's builtin
unlink()
function for removing files, see "unlink" in perlfunc. utime
-
This is identical to Perl's builtin
utime()
function for changing the time stamps of files and directories, see "utime" in perlfunc. vfprintf
-
Not implemented.
vfprintf()
is C-specific, see "printf" in perlfunc instead. vprintf
-
Not implemented.
vprintf()
is C-specific, see "printf" in perlfunc instead. vsprintf
-
Not implemented.
vsprintf()
is C-specific, see "sprintf" in perlfunc instead. wait
-
This is identical to Perl's builtin
wait()
function, see "wait" in perlfunc. waitpid
-
Wait for a child process to change state. This is identical to Perl's builtin
waitpid()
function, see "waitpid" in perlfunc.$pid = POSIX::waitpid( -1, POSIX::WNOHANG ); print "status = ", ($? / 256), "\n";
wcstombs
-
This is identical to the C function
wcstombs()
.See "mblen".
wctomb
-
This is identical to the C function
wctomb()
.See "mblen".
write
-
Write to a file. This uses file descriptors such as those obtained by calling
POSIX::open
.$fd = POSIX::open( "foo", &POSIX::O_WRONLY ); $buf = "hello"; $bytes = POSIX::write( $fd, $buf, 5 );
Returns
undef
on failure.See also "syswrite" in perlfunc.
CLASSES
POSIX::SigAction
new
-
Creates a new
POSIX::SigAction
object which corresponds to the Cstruct sigaction
. This object will be destroyed automatically when it is no longer needed. The first parameter is the handler, a sub reference. The second parameter is aPOSIX::SigSet
object, it defaults to the empty set. The third parameter contains thesa_flags
, it defaults to 0.$sigset = POSIX::SigSet->new(SIGINT, SIGQUIT); $sigaction = POSIX::SigAction->new( \&handler, $sigset, &POSIX::SA_NOCLDSTOP );
This
POSIX::SigAction
object is intended for use with thePOSIX::sigaction()
function.
handler
mask
flags
-
accessor functions to get/set the values of a SigAction object.
$sigset = $sigaction->mask; $sigaction->flags(&POSIX::SA_RESTART);
safe
-
accessor function for the "safe signals" flag of a SigAction object; see perlipc for general information on safe (a.k.a. "deferred") signals. If you wish to handle a signal safely, use this accessor to set the "safe" flag in the
POSIX::SigAction
object:$sigaction->safe(1);
You may also examine the "safe" flag on the output action object which is filled in when given as the third parameter to
POSIX::sigaction()
:sigaction(SIGINT, $new_action, $old_action); if ($old_action->safe) { # previous SIGINT handler used safe signals }
POSIX::SigRt
%SIGRT
-
A hash of the POSIX realtime signal handlers. It is an extension of the standard
%SIG
, the$POSIX::SIGRT{SIGRTMIN}
is roughly equivalent to$SIG{SIGRTMIN}
, but the right POSIX moves (see below) are made with thePOSIX::SigSet
andPOSIX::sigaction
instead of accessing the%SIG
.You can set the
%POSIX::SIGRT
elements to set the POSIX realtime signal handlers, usedelete
andexists
on the elements, and usescalar
on the%POSIX::SIGRT
to find out how many POSIX realtime signals there are available(SIGRTMAX - SIGRTMIN + 1
, theSIGRTMAX
is a valid POSIX realtime signal).Setting the
%SIGRT
elements is equivalent to calling this:sub new { my ($rtsig, $handler, $flags) = @_; my $sigset = POSIX::SigSet($rtsig); my $sigact = POSIX::SigAction->new($handler,$sigset,$flags); sigaction($rtsig, $sigact); }
The flags default to zero, if you want something different you can either use
local
on$POSIX::SigRt::SIGACTION_FLAGS
, or you can derive from POSIX::SigRt and define your ownnew()
(the tied hash STORE method of the%SIGRT
callsnew($rtsig, $handler, $SIGACTION_FLAGS)
, where the$rtsig
ranges from zero toSIGRTMAX - SIGRTMIN + 1)
.Just as with any signal, you can use
sigaction($rtsig, undef, $oa)
to retrieve the installed signal handler (or, rather, the signal action).NOTE: whether POSIX realtime signals really work in your system, or whether Perl has been compiled so that it works with them, is outside of this discussion.
SIGRTMIN
-
Return the minimum POSIX realtime signal number available, or
undef
if no POSIX realtime signals are available. SIGRTMAX
-
Return the maximum POSIX realtime signal number available, or
undef
if no POSIX realtime signals are available.
POSIX::SigSet
new
-
Create a new SigSet object. This object will be destroyed automatically when it is no longer needed. Arguments may be supplied to initialize the set.
Create an empty set.
$sigset = POSIX::SigSet->new;
Create a set with
SIGUSR1
.$sigset = POSIX::SigSet->new( &POSIX::SIGUSR1 );
addset
-
Add a signal to a SigSet object.
$sigset->addset( &POSIX::SIGUSR2 );
Returns
undef
on failure. delset
-
Remove a signal from the SigSet object.
$sigset->delset( &POSIX::SIGUSR2 );
Returns
undef
on failure. emptyset
-
Initialize the SigSet object to be empty.
$sigset->emptyset();
Returns
undef
on failure. fillset
-
Initialize the SigSet object to include all signals.
$sigset->fillset();
Returns
undef
on failure. ismember
-
Tests the SigSet object to see if it contains a specific signal.
if( $sigset->ismember( &POSIX::SIGUSR1 ) ){ print "contains SIGUSR1\n"; }
POSIX::Termios
new
-
Create a new Termios object. This object will be destroyed automatically when it is no longer needed. A Termios object corresponds to the
termios
C struct.new()
mallocs a new one,getattr()
fills it from a file descriptor, andsetattr()
sets a file descriptor's parameters to match Termios' contents.$termios = POSIX::Termios->new;
getattr
-
Get terminal control attributes.
Obtain the attributes for
stdin
.$termios->getattr( 0 ) # Recommended for clarity. $termios->getattr()
Obtain the attributes for stdout.
$termios->getattr( 1 )
Returns
undef
on failure. getcc
-
Retrieve a value from the
c_cc
field of atermios
object. Thec_cc
field is an array so an index must be specified.$c_cc[1] = $termios->getcc(1);
getcflag
-
Retrieve the
c_cflag
field of atermios
object.$c_cflag = $termios->getcflag;
getiflag
-
Retrieve the
c_iflag
field of atermios
object.$c_iflag = $termios->getiflag;
getispeed
-
Retrieve the input baud rate.
$ispeed = $termios->getispeed;
getlflag
-
Retrieve the
c_lflag
field of atermios
object.$c_lflag = $termios->getlflag;
getoflag
-
Retrieve the
c_oflag
field of atermios
object.$c_oflag = $termios->getoflag;
getospeed
-
Retrieve the output baud rate.
$ospeed = $termios->getospeed;
setattr
-
Set terminal control attributes.
Set attributes immediately for stdout.
$termios->setattr( 1, &POSIX::TCSANOW );
Returns
undef
on failure. setcc
-
Set a value in the
c_cc
field of atermios
object. Thec_cc
field is an array so an index must be specified.$termios->setcc( &POSIX::VEOF, 1 );
setcflag
-
Set the
c_cflag
field of atermios
object.$termios->setcflag( $c_cflag | &POSIX::CLOCAL );
setiflag
-
Set the
c_iflag
field of atermios
object.$termios->setiflag( $c_iflag | &POSIX::BRKINT );
setispeed
-
Set the input baud rate.
$termios->setispeed( &POSIX::B9600 );
Returns
undef
on failure. setlflag
-
Set the
c_lflag
field of atermios
object.$termios->setlflag( $c_lflag | &POSIX::ECHO );
setoflag
-
Set the
c_oflag
field of atermios
object.$termios->setoflag( $c_oflag | &POSIX::OPOST );
setospeed
-
Set the output baud rate.
$termios->setospeed( &POSIX::B9600 );
Returns
undef
on failure. - Baud rate values
-
B38400
B75
B200
B134
B300
B1800
B150
B0
B19200
B1200
B9600
B600
B4800
B50
B2400
B110
- Terminal interface values
-
TCSADRAIN
TCSANOW
TCOON
TCIOFLUSH
TCOFLUSH
TCION
TCIFLUSH
TCSAFLUSH
TCIOFF
TCOOFF
c_cc
field values-
VEOF
VEOL
VERASE
VINTR
VKILL
VQUIT
VSUSP
VSTART
VSTOP
VMIN
VTIME
NCCS
c_cflag
field values-
CLOCAL
CREAD
CSIZE
CS5
CS6
CS7
CS8
CSTOPB
HUPCL
PARENB
PARODD
c_iflag
field values-
BRKINT
ICRNL
IGNBRK
IGNCR
IGNPAR
INLCR
INPCK
ISTRIP
IXOFF
IXON
PARMRK
c_lflag
field values-
ECHO
ECHOE
ECHOK
ECHONL
ICANON
IEXTEN
ISIG
NOFLSH
TOSTOP
c_oflag
field values-
OPOST
PATHNAME CONSTANTS
- Constants
-
_PC_CHOWN_RESTRICTED
_PC_LINK_MAX
_PC_MAX_CANON
_PC_MAX_INPUT
_PC_NAME_MAX
_PC_NO_TRUNC
_PC_PATH_MAX
_PC_PIPE_BUF
_PC_VDISABLE
POSIX CONSTANTS
- Constants
-
_POSIX_ARG_MAX
_POSIX_CHILD_MAX
_POSIX_CHOWN_RESTRICTED
_POSIX_JOB_CONTROL
_POSIX_LINK_MAX
_POSIX_MAX_CANON
_POSIX_MAX_INPUT
_POSIX_NAME_MAX
_POSIX_NGROUPS_MAX
_POSIX_NO_TRUNC
_POSIX_OPEN_MAX
_POSIX_PATH_MAX
_POSIX_PIPE_BUF
_POSIX_SAVED_IDS
_POSIX_SSIZE_MAX
_POSIX_STREAM_MAX
_POSIX_TZNAME_MAX
_POSIX_VDISABLE
_POSIX_VERSION
SYSTEM CONFIGURATION
- Constants
-
_SC_ARG_MAX
_SC_CHILD_MAX
_SC_CLK_TCK
_SC_JOB_CONTROL
_SC_NGROUPS_MAX
_SC_OPEN_MAX
_SC_PAGESIZE
_SC_SAVED_IDS
_SC_STREAM_MAX
_SC_TZNAME_MAX
_SC_VERSION
ERRNO
- Constants
-
E2BIG
EACCES
EADDRINUSE
EADDRNOTAVAIL
EAFNOSUPPORT
EAGAIN
EALREADY
EBADF
EBADMSG
EBUSY
ECANCELED
ECHILD
ECONNABORTED
ECONNREFUSED
ECONNRESET
EDEADLK
EDESTADDRREQ
EDOM
EDQUOT
EEXIST
EFAULT
EFBIG
EHOSTDOWN
EHOSTUNREACH
EIDRM
EILSEQ
EINPROGRESS
EINTR
EINVAL
EIO
EISCONN
EISDIR
ELOOP
EMFILE
EMLINK
EMSGSIZE
ENAMETOOLONG
ENETDOWN
ENETRESET
ENETUNREACH
ENFILE
ENOBUFS
ENODATA
ENODEV
ENOENT
ENOEXEC
ENOLCK
ENOLINK
ENOMEM
ENOMSG
ENOPROTOOPT
ENOSPC
ENOSR
ENOSTR
ENOSYS
ENOTBLK
ENOTCONN
ENOTDIR
ENOTEMPTY
ENOTRECOVERABLE
ENOTSOCK
ENOTSUP
ENOTTY
ENXIO
EOPNOTSUPP
EOTHER
EOVERFLOW
EOWNERDEAD
EPERM
EPFNOSUPPORT
EPIPE
EPROCLIM
EPROTO
EPROTONOSUPPORT
EPROTOTYPE
ERANGE
EREMOTE
ERESTART
EROFS
ESHUTDOWN
ESOCKTNOSUPPORT
ESPIPE
ESRCH
ESTALE
ETIME
ETIMEDOUT
ETOOMANYREFS
ETXTBSY
EUSERS
EWOULDBLOCK
EXDEV
FCNTL
- Constants
-
FD_CLOEXEC
F_DUPFD
F_GETFD
F_GETFL
F_GETLK
F_OK
F_RDLCK
F_SETFD
F_SETFL
F_SETLK
F_SETLKW
F_UNLCK
F_WRLCK
O_ACCMODE
O_APPEND
O_CREAT
O_EXCL
O_NOCTTY
O_NONBLOCK
O_RDONLY
O_RDWR
O_TRUNC
O_WRONLY
FLOAT
- Constants
-
DBL_DIG
DBL_EPSILON
DBL_MANT_DIG
DBL_MAX
DBL_MAX_10_EXP
DBL_MAX_EXP
DBL_MIN
DBL_MIN_10_EXP
DBL_MIN_EXP
FLT_DIG
FLT_EPSILON
FLT_MANT_DIG
FLT_MAX
FLT_MAX_10_EXP
FLT_MAX_EXP
FLT_MIN
FLT_MIN_10_EXP
FLT_MIN_EXP
FLT_RADIX
FLT_ROUNDS
LDBL_DIG
LDBL_EPSILON
LDBL_MANT_DIG
LDBL_MAX
LDBL_MAX_10_EXP
LDBL_MAX_EXP
LDBL_MIN
LDBL_MIN_10_EXP
LDBL_MIN_EXP
FLOATING-POINT ENVIRONMENT
- Constants
-
FE_DOWNWARD
FE_TONEAREST
FE_TOWARDZERO
FE_UPWARD
on systems that support them.
LIMITS
- Constants
-
ARG_MAX
CHAR_BIT
CHAR_MAX
CHAR_MIN
CHILD_MAX
INT_MAX
INT_MIN
LINK_MAX
LONG_MAX
LONG_MIN
MAX_CANON
MAX_INPUT
MB_LEN_MAX
NAME_MAX
NGROUPS_MAX
OPEN_MAX
PATH_MAX
PIPE_BUF
SCHAR_MAX
SCHAR_MIN
SHRT_MAX
SHRT_MIN
SSIZE_MAX
STREAM_MAX
TZNAME_MAX
UCHAR_MAX
UINT_MAX
ULONG_MAX
USHRT_MAX
LOCALE
- Constants
-
LC_ALL
LC_COLLATE
LC_CTYPE
LC_MONETARY
LC_NUMERIC
LC_TIME
LC_MESSAGES
on systems that support them.
MATH
- Constants
-
HUGE_VAL
FP_ILOGB0
FP_ILOGBNAN
FP_INFINITE
FP_NAN
FP_NORMAL
FP_SUBNORMAL
FP_ZERO
INFINITY
NAN
Inf
NaN
M_1_PI
M_2_PI
M_2_SQRTPI
M_E
M_LN10
M_LN2
M_LOG10E
M_LOG2E
M_PI
M_PI_2
M_PI_4
M_SQRT1_2
M_SQRT2
on systems with C99 support.
SIGNAL
- Constants
-
SA_NOCLDSTOP
SA_NOCLDWAIT
SA_NODEFER
SA_ONSTACK
SA_RESETHAND
SA_RESTART
SA_SIGINFO
SIGABRT
SIGALRM
SIGCHLD
SIGCONT
SIGFPE
SIGHUP
SIGILL
SIGINT
SIGKILL
SIGPIPE
SIGQUIT
SIGSEGV
SIGSTOP
SIGTERM
SIGTSTP
SIGTTIN
SIGTTOU
SIGUSR1
SIGUSR2
SIG_BLOCK
SIG_DFL
SIG_ERR
SIG_IGN
SIG_SETMASK
SIG_UNBLOCK
STAT
- Constants
-
S_IRGRP
S_IROTH
S_IRUSR
S_IRWXG
S_IRWXO
S_IRWXU
S_ISGID
S_ISUID
S_IWGRP
S_IWOTH
S_IWUSR
S_IXGRP
S_IXOTH
S_IXUSR
- Macros
-
S_ISBLK
S_ISCHR
S_ISDIR
S_ISFIFO
S_ISREG
STDLIB
- Constants
-
EXIT_FAILURE
EXIT_SUCCESS
MB_CUR_MAX
RAND_MAX
STDIO
- Constants
-
BUFSIZ
EOF
FILENAME_MAX
L_ctermid
L_cuserid
L_tmpname
TMP_MAX
TIME
- Constants
-
CLK_TCK
CLOCKS_PER_SEC
UNISTD
- Constants
-
R_OK
SEEK_CUR
SEEK_END
SEEK_SET
STDIN_FILENO
STDOUT_FILENO
STDERR_FILENO
W_OK
X_OK
WAIT
- Constants
-
WNOHANG
WUNTRACED
WNOHANG
-
Do not suspend the calling process until a child process changes state but instead return immediately.
WUNTRACED
-
Catch stopped child processes.
- Macros
-
WIFEXITED
WEXITSTATUS
WIFSIGNALED
WTERMSIG
WIFSTOPPED
WSTOPSIG
WIFEXITED
-
WIFEXITED(${^CHILD_ERROR_NATIVE})
returns true if the child process exited normally (exit()
or by falling off the end ofmain()
) WEXITSTATUS
-
WEXITSTATUS(${^CHILD_ERROR_NATIVE})
returns the normal exit status of the child process (only meaningful ifWIFEXITED(${^CHILD_ERROR_NATIVE})
is true) WIFSIGNALED
-
WIFSIGNALED(${^CHILD_ERROR_NATIVE})
returns true if the child process terminated because of a signal WTERMSIG
-
WTERMSIG(${^CHILD_ERROR_NATIVE})
returns the signal the child process terminated for (only meaningful ifWIFSIGNALED(${^CHILD_ERROR_NATIVE})
is true) WIFSTOPPED
-
WIFSTOPPED(${^CHILD_ERROR_NATIVE})
returns true if the child process is currently stopped (can happen only if you specified the WUNTRACED flag towaitpid()
) WSTOPSIG
-
WSTOPSIG(${^CHILD_ERROR_NATIVE})
returns the signal the child process was stopped for (only meaningful ifWIFSTOPPED(${^CHILD_ERROR_NATIVE})
is true)