CentOS 7.0 - man page for getdtablesize (centos section 3)

GETDTABLESIZE(3)		    Linux Programmer's Manual			 GETDTABLESIZE(3)

NAME
       getdtablesize - get descriptor table size

SYNOPSIS
       #include <unistd.h>

       int getdtablesize(void);

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       getdtablesize():
	   Since glibc 2.12:
	       _BSD_SOURCE ||
		   !(_POSIX_C_SOURCE >= 200112L || _XOPEN_SOURCE >= 600)
	   Before glibc 2.12:
	       _BSD_SOURCE || _XOPEN_SOURCE >= 500 || _XOPEN_SOURCE && _XOPEN_SOURCE_EXTENDED

DESCRIPTION
       getdtablesize() returns the maximum number of files a process can have open, one more than
       the largest possible value for a file descriptor.

RETURN VALUE
       The current limit on the number of open files per process.

ERRORS
       On Linux, getdtablesize() can return any of the errors  described  for  getrlimit(2);  see
       NOTES below.

CONFORMING TO
       SVr4, 4.4BSD (the getdtablesize() function first appeared in 4.2BSD).  It is not specified
       in POSIX.1-2001; portable applications should employ sysconf(_SC_OPEN_MAX) instead of this
       call.

NOTES
       getdtablesize()	is implemented as a libc library function.  The glibc version calls getr-
       limit(2) and returns the current RLIMIT_NOFILE limit, or OPEN_MAX when  that  fails.   The
       libc4 and libc5 versions return OPEN_MAX (set to 256 since Linux 0.98.4).

SEE ALSO
       close(2), dup(2), getrlimit(2), open(2)

COLOPHON
       This  page  is  part of release 3.53 of the Linux man-pages project.  A description of the
       project,    and	  information	 about	  reporting    bugs,	can    be    found     at
       http://www.kernel.org/doc/man-pages/.

Linux					    2013-02-05				 GETDTABLESIZE(3)