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 3.54 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/.