strnlen - determine the length of a fixed-size string
Standard C library (
libc,
-lc)
#include <string.h>
size_t strnlen(const char s[.maxlen], size_t maxlen);
strnlen():
Since glibc 2.10:
_POSIX_C_SOURCE >= 200809L
Before glibc 2.10:
_GNU_SOURCE
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].
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).
Interface |
Attribute |
Value |
strnlen () |
Thread safety |
MT-Safe |
POSIX.1-2008.
strlen(3)