strlen() — Determine string length

Standards

Standards / Extensions	C or C++	Dependencies
ISO C POSIX.1 XPG4 XPG4.2 C99 Single UNIX Specification, Version 3	both

Format

#include <string.h>

size_t strlen(const char *string);

General description

The strlen() built-in function determines the length of string pointed to by string, excluding the terminating NULL character.

Returned value

strlen() returns the length of string.

Example

CELEBS43

⁄* CELEBS43                                      

   This example determines the length of the string that is                     
   passed to main.                                                              
                                                                                
 *⁄                                                                             
#include <stdio.h>                                                              
#include <string.h>                                                             
                                                                                
int main(int argc, char **argv)                                                 
{                                                                               
                                                                                
  if ( argc != 2 )                                                              
    printf( "Usage: %s string\n", argv[0] );                                    
  else                                                                          
    printf( "Input string has a length of %i\n", strlen( argv[1] ));            
}

Output

If the input is the string: "How long is this string?", then the expected output is:

Input string has a length of 24