strnlen - determine the length of a fixed-size string
size_t strnlen(const char *s, size_t maxlen);
Since glibc 2.10:
_POSIX_C_SOURCE >= 200809L
Before glibc 2.10:
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
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.
For an explanation of the terms used in this section, see attributes(7).
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