< c‎ | string‎ | byte
Defined in header <string.h>
size_t strlen( const char *str );

Returns the length of the given byte string.

The null character is excluded from the length.


[edit] Parameters

str - pointer to the null-terminated byte string to be examined

[edit] Return value

The length of the null-terminated string str.

[edit] Example

#include <string.h>
#include <stdio.h>
int main(void)
    const char str[] = "How many characters does this string contain?";
    printf("without null character: %zu\n", strlen(str));
    printf("with null character: %zu\n", sizeof(str));
    return 0;


without null character: 45
with null character: 46

[edit] See also

C++ documentation for strlen