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).
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
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