1GETDTABLESIZE(3)           Linux Programmer's Manual          GETDTABLESIZE(3)
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NAME

6       getdtablesize - get descriptor table size
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SYNOPSIS

9       #include <unistd.h>
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11       int getdtablesize(void);
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13   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
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15       getdtablesize():
16           Since glibc 2.12:
17               _BSD_SOURCE ||
18                   !(_POSIX_C_SOURCE >= 200112L || _XOPEN_SOURCE >= 600)
19           Before glibc 2.12:
20               _BSD_SOURCE || _XOPEN_SOURCE >= 500 ||
21               _XOPEN_SOURCE && _XOPEN_SOURCE_EXTENDED
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DESCRIPTION

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

28       The current limit on the number of open files per process.
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ERRORS

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

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

40       getdtablesize() is implemented as a libc library function.   The  glibc
41       version calls getrlimit(2) and returns the current RLIMIT_NOFILE limit,
42       or OPEN_MAX when that fails.   The  libc4  and  libc5  versions  return
43       OPEN_MAX (set to 256 since Linux 0.98.4).
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SEE ALSO

46       close(2), dup(2), getrlimit(2), open(2)
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COLOPHON

49       This  page  is  part of release 3.53 of the Linux man-pages project.  A
50       description of the project, and information about reporting  bugs,  can
51       be found at http://www.kernel.org/doc/man-pages/.
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55Linux                             2013-02-05                  GETDTABLESIZE(3)