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strlen(3) Library Functions Manual 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').

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
strlen () Thread safety MT-Safe

STANDARDS

POSIX.1-2001, POSIX.1-2008, 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)

2023-02-05 Linux man-pages 6.03