strlen(3)

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).
Interface | Attribute | Value
 | Thread safety | MT-Safe

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)