NAME

       strnlen - determine the length of a fixed-size string

LIBRARY

       Standard C library (libc, -lc)

SYNOPSIS

       #include <string.h>

       size_t strnlen(const char s[.maxlen], size_t maxlen);

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

       strnlen():
           Since glibc 2.10:
               _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 characters in the string pointed to by s and never beyond
       s[maxlen-1].

RETURN VALUE

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

ATTRIBUTES

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

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

STANDARDS

       POSIX.1-2008.

HISTORY

       POSIX.1-2008.

SEE ALSO

       strlen(3)