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

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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Linux                                              2020-06-09                                   GETDTABLESIZE(3)