STRNLEN(3)

NAME
strnlen - determine the length of a fixed-size string

SYNOPSIS
#include <string.h>

size_t strnlen(const char *s, size_t maxlen);

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

strnlen():
    Since glibc 2.10:
        _XOPEN_SOURCE >= 700 || _POSIX_C_SOURCE >= 200809L
    Before glibc 2.10:
        _GNU_SOURCE

DESCRIPTION
The strnlen() function returns the number of bytes in the string pointed to by s, excluding the terminating null byte ('\0'), but at most maxlen. In doing this, strnlen() looks only at the first maxlen bytes at s and never beyond s+maxlen.

RETURN VALUE
The strnlen() function returns strlen(s), if that is less than maxlen, or maxlen if there is no null byte ('\0') among the first maxlen bytes pointed to by s.

ATTRIBUTES

  Multithreading (see pthreads(7))
The strnlen() function is thread-safe.

CONFORMING TO
POSIX.1-2008.

SEE ALSO
strlen(3)

COLOPHON
This page is part of release 3.65 of the Linux man-pages project. A description of the project, and information about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.