Remaining Functions

The two remaining functions of the string-handling library are strerror and strlen.

Following Table summarizes the strerror and strlen functions.

Function strerror

Function strerror takes an error number and creates an error message string. A pointer to the string is returned. The example demonstrates strerror.

Example:

/*how to use strerror*/

#include <stdio.h>
#include <string.h>

int main( void )
{
printf( "%s\n", strerror( 2 ) );

return 0;
}

Output:

No such file or directory

Function strlen

Function strlen takes a string as an argument and returns the number of characters in the string the terminating null character is not included in the length. The example demonstrates function strlen.

Example:

/*how to use strerror*/

#include <stdio.h>
#include <string.h>

int main( void )
{
/* initialize 3 char pointers */
const char *string1 = "abcdefghijklmnopqrstuvwxyz";
const char *string2 = "Ricky";
const char *string3 = "Martin";

printf("%s\"%s\"%s%lu\n%s\"%s\"%s%lu\n%s\"%s\"%s%lu\n",
"The length of ", string1, " is ",
( unsigned long ) strlen( string1 ),
"The length of ", string2, " is ",
( unsigned long ) strlen( string2 ),
"The length of ", string3, " is ",
( unsigned long ) strlen( string3 ),

return 0;
}

Output:

The length of "abcdefghijklmnopqrstuvwxyz" is 26

The length of "four" is 5

The length of "Boston" is 6