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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 getrlimit(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)