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

GETDTABLESIZE(3)          Linux Programmer's Manual         GETDTABLESIZE(3)

NAME         top

       getdtablesize - get file descriptor table size

SYNOPSIS         top

       #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         top

       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         top

       The current limit on the number of open files per process.

ERRORS         top

       On Linux, getdtablesize() can return any of the errors described for
       getrlimit(2); see NOTES below.

ATTRIBUTES         top

       For an explanation of the terms used in this section, see
       attributes(7).

       ┌────────────────┬───────────────┬─────────┐
       │Interface       Attribute     Value   │
       ├────────────────┼───────────────┼─────────┤
       │getdtablesize() │ Thread safety │ MT-Safe │
       └────────────────┴───────────────┴─────────┘

CONFORMING TO         top

       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         top

       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         top

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

COLOPHON         top

       This page is part of release 4.07 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/.

Linux                            2016-03-15                 GETDTABLESIZE(3)