strlen - Man Page

calculate the length of a string

Synopsis

#include <string.h>

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 bytes in the string pointed to by s.

Attributes

For an explanation of the terms used in this section, see attributes(7).

InterfaceAttributeValue
strlen()Thread safetyMT-Safe

Conforming to

POSIX.1-2001, POSIX.1-2008, C89, C99, C11, SVr4, 4.3BSD.

Notes

In cases where the input buffer may not contain a terminating null byte, strnlen(3) should be used instead.

See Also

string(3), strnlen(3), wcslen(3), wcsnlen(3)

Colophon

This page is part of release 5.13 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/.

Referenced By

lber-types(3), OSSL_PARAM_int.3ossl(3), pmfstring(3), regex(3), signal-safety(7), strchr(3), str_copy(3), str_diff(3), str_diffn(3), str_equal(3), string(3), str_len(3), strnlen(3), waffle_error(3), wcslen(3).

2021-08-27 GNU Linux Programmer's Manual