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:
_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.
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 |
Conforming to
POSIX.1-2008.
See Also
Colophon
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Referenced By
signal-safety(7), strlen(3), wcsnlen(3).