GETDTABLESIZE
Section: Linux Programmer's Manual (3)
Updated: 2020-06-09
Page Index
NAME
getdtablesize - get file 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:
-
/* 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
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.
ATTRIBUTES
For an explanation of the terms used in this section, see
attributes(7).
| Interface | Attribute | Value
|
|
getdtablesize()
| Thread safety | MT-Safe
|
CONFORMING TO
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.
NOTES
The glibc version of
getdtablesize()
calls
getrlimit(2)
and returns the current
RLIMIT_NOFILE
limit, or
OPEN_MAX
when that fails.
SEE ALSO
close(2),
dup(2),
getrlimit(2),
open(2)
COLOPHON
This page is part of release 5.10 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/.