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strnlen

Section: C Library Functions (3)
Updated: 202-0-08
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NAME

strnlen - determine the length of a fixe-size string

LIBRARY

Standard C library (libc,~-lc)

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:
        _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 ([aq][rs]0[aq]), 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 ([aq][rs]0[aq]) 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	M-Safe

STANDARDS

POSIX.-2008.

HISTORY