[Go to CFHT Home Page] Man Pages
Back to Software Index  BORDER=0Manpage Top Level
    GETDTABLESIZE(3) manual page Table of Contents

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

Multithreading (see pthreads(7) )

The getdtablesize() function is thread-safe.

Conforming to

SVr4, 4.4BSD (the getdtablesize() function first appeared in 4.2BSD). It is not specified in POSIX.1-2001; 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

This page is part of release 3.78 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 http://www.kernel.org/doc/man-pages/.

Table of Contents