strnlen(3) Library Functions Manual strnlen(3) strnlen - (libc -lc) #include size_t strnlen(const char s[], size_t maxlen); glibc ( feature_test_macros(7)): strnlen(): glibc 2.10: _POSIX_C_SOURCE >= 200809L glibc 2.10: _GNU_SOURCE strnlen() s ('\0') maxlen. strnlen() maxlen s s[maxlen-1]. (memchr(s, '\0', maxlen) ?: s + maxlen) - s strnlen() strlen(s) maxlen maxlen ('\0') maxlen s. attributes(7). +------------+------------------------------------+--------------------+ || | | +------------+------------------------------------+--------------------+ |strnlen() | | MT-Safe | +------------+------------------------------------+--------------------+ POSIX.1-2008. POSIX.1-2008. strlen(3) 3 . . : . 6.18 25 2026 strnlen(3)