countof(3)                 Library Functions Manual                 countof(3)

NAME
       countof, _Countof - count the number of elements in an array

LIBRARY
       Standard C library (libc)

SYNOPSIS
       #include <stdcountof.h>

       size_t countof(array);

DESCRIPTION
       This operator counts the number of elements in an array.

       If the operand is not an array, it produces a compilation error.

       There's a keyword, _Countof(), that behaves identically, and can be
       used without including <stdcountof.h>.

RETURN VALUE
       The number of elements in the array.

STANDARDS
       C2y.

HISTORY
       gcc 16, clang 21.

SEE ALSO
       operator(7)

Linux man-pages 6.16              2025-08-19                        countof(3)