STRNLEN(3)                          Linux Programmer's Manual                          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, exclud‐
       ing 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 3.74 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 http://www.kernel.org/doc/man-pages/.



GNU                                         2014-02-25                                 STRNLEN(3)