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NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | ATTRIBUTES | CONFORMING TO | NOTES | SEE ALSO | COLOPHON |
GETDTABLESIZE(3) Linux Programmer's Manual GETDTABLESIZE(3)
getdtablesize - get file descriptor table size
#include <unistd.h>
int getdtablesize(void);
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
getdtablesize():
Since glibc 2.12:
/* Glibc since 2.19: */ _DEFAULT_SOURCE
|| /* Glibc versions <= 2.19: */ _BSD_SOURCE
|| ! (_POSIX_C_SOURCE >= 200112L)
Before glibc 2.12:
_BSD_SOURCE || _XOPEN_SOURCE >= 500
getdtablesize() returns the maximum number of files a process can
have open, one more than the largest possible value for a file
descriptor.
The current limit on the number of open files per process.
On Linux, getdtablesize() can return any of the errors described for
getrlimit(2); see NOTES below.
For an explanation of the terms used in this section, see
attributes(7).
┌────────────────┬───────────────┬─────────┐
│Interface │ Attribute │ Value │
├────────────────┼───────────────┼─────────┤
│getdtablesize() │ Thread safety │ MT-Safe │
└────────────────┴───────────────┴─────────┘
SVr4, 4.4BSD (the getdtablesize() function first appeared in 4.2BSD).
It is not specified in POSIX.1; portable applications should employ
sysconf(_SC_OPEN_MAX) instead of this call.
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.
close(2), dup(2), getrlimit(2), open(2)
This page is part of release 4.12 of the Linux man-pages project. A
description of the project, information about reporting bugs, and the
latest version of this page, can be found at
https://www.kernel.org/doc/man-pages/.
Linux 2016-03-15 GETDTABLESIZE(3)