NAME¶

strlen - calculate the length of a string

LIBRARY¶

Standard C library (libc, -lc)

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').

It is equivalent to

strnul(s) - s

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).

STANDARDS¶

C11, POSIX.1-2008.

HISTORY¶

POSIX.1-2001, C89, 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), strnul(3), wcslen(3), wcsnlen(3)