Perl in a Nutshell

POSIX

Provides access to standard POSIX 1003.1 identifiers: functions, classes, and constants. Can be used to import one or multiple symbols:

use POSIX;                        # import all symbols
use POSIX qw(setsid);             # import one symbol
use POSIX qw(:errno_h :fcntl_h);  # import sets of symbols

Functions listed as C-specific are not implemented.

_exit	Identical to C function _exit(2)
abort	Identical to C function abort(3)
abs	Identical to Perl’s abs function
access	Determines accessibility of a file; returns undef on failure
acos	Identical to C function acos(3)
alarm	Identical to Perl’s alarm function
asctime	Identical to C function asctime(3)
asin	Identical to C function asin(3)
assert	Similar to C macro assert(3)
atan	Identical to C function atan(3)
atan2	Identical to Perl’s atan2 function
atexit	C-specific; use END {}
atof	C-specific
atoi	C-specific
atol	C-specific
bsearch	Not supplied
calloc	C-specific
ceil	Identical to C function ceil(3)
chdir	Identical to Perl’s chdir function
chmod	Identical to Perl’s chmod function
chown	Identical to Perl’s chown function
clearerr	Uses method FileHandle::clearerr
clock	Identical to C function clock(3)
close	Closes a file; returns undef on failure
closedir	Identical to Perl’s closedir function
cos	Identical to Perl’s cos function
cosh	Identical to C function cosh(3)
creat	Creates a new file
ctermid	Generates path name for the controlling terminal
ctime	Identical to C function ctime(3)
cuserid	Gets user’s ...