NAME

strlen − Find the length of a string

SYNOPSIS

#include <string.h>
size_t strlen(
        const char ∗s );

LIBRARY

Standard C Library (libc)

STANDARDS

Interfaces documented on this reference page conform to industry standards as follows:

strlen(): ISO C, XPG4

Refer to the standards(5) reference page for more information about industry standards and associated tags. 

PARAMETERS

sSpecifies the string. 

DESCRIPTION

The strlen() function returns the number of bytes in the string pointed to by the s parameter. The string length value does not include the terminating null character. 

Note

If you pass a NULL pointer as the const char ∗ parameter to the strlen function, the function generates a segmentation violation. To avoid the segmentation violation and cause the function to return 0 (zero), change the NULL pointer treatment for the process before issuing the call to the strlen function, as follows:

     1.Include the system header file sys/uswitch.h. 

     2.Call the uswitch function, as described in the uswitch(2) reference page. 

The following program illustrates this procedure:

#include <stdio.h>
#include <sys/types.h>
#include <sys/uswitch.h>
main()
{
        size_t  retval;
        int     uswitch_val;
        uswitch_val = uswitch(USC_GET,0);
        uswitch(USC_SET, uswitch_val | USW_NULLP);
        retval = strlen(NULL);

RETURN VALUES

On successful completion, the strlen() function returns the number of characters (bytes) in the string to which the s parameter points. Current industry standards specify that no value be reserved to indicate an error. 

SEE ALSO

Functions: string(3), uswitch(2), wcslen(3)

Standards: standards(5)