STRLEN(3) Linux Programmer's Manual STRLEN(3) NAME strlen - calculate the length of a string SYNOPSIS #include size_t strlen(const char *s); DESCRIPTION The strlen() function calculates the length of the string pointed to by s, excluding the terminating null byte ('\0'). RETURN VALUE The strlen() function returns the number of characters in the string pointed to by s. ATTRIBUTES For an explanation of the terms used in this section, see attributes(7). +----------+---------------+---------+ |Interface | Attribute | Value | +----------+---------------+---------+ |strlen() | Thread safety | MT-Safe | +----------+---------------+---------+ CONFORMING TO POSIX.1-2001, POSIX.1-2008, C89, C99, C11, SVr4, 4.3BSD. SEE ALSO string(3), strnlen(3), wcslen(3), wcsnlen(3) COLOPHON This page is part of release 4.16 of the Linux man-pages project. A description of the project, information about reporting bugs, and the latest version of this page, can be found at https://www.kernel.org/doc/man-pages/. GNU 2016-03-15 STRLEN(3)