NAME¶

getdtablesize - get file descriptor table size

SYNOPSIS¶

#include <unistd.h>

int getdtablesize(void);

getdtablesize():

    Since glibc 2.20:


        _DEFAULT_SOURCE || ! (_POSIX_C_SOURCE >= 200112L)


    Glibc 2.12 to 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¶

This page is part of release 5.13 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/.