Manpages - getdtablesize.3

getdtablesize - get file descriptor table size

  #include <unistd.h>

  int getdtablesize(void);

Feature Test Macro Requirements for glibc (see *feature_test_macros*(7)):

*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

*getdtablesize*() returns the maximum number of files a process can have open, one more than the largest possible value for a file descriptor.

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

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

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

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.

The glibc version of getdtablesize*() calls *getrlimit*(2) and returns the current *RLIMIT_NOFILE limit, or OPEN_MAX when that fails.

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

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