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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

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