Man Pages

GETDTABLESIZE


NAME
SYNOPSIS
DESCRIPTION
RETURN VALUE
ERRORS
ATTRIBUTES
CONFORMING TO
NOTES
SEE ALSO
COLOPHON

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.

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

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.

SEE ALSO

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

COLOPHON

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