strlen(3)strlen(3)NAMEstrlen - 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 stan‐
dards as follows:
strlen(): ISO C, XPG4
Refer to the standards(5) reference page for more information about
industry standards and associated tags.
PARAMETERS
Specifies 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: Include the system header file
sys/uswitch.h. 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. Cur‐
rent industry standards specify that no value be reserved to indicate
an error.
SEE ALSO
Functions: string(3), uswitch(2), wcslen(3)
Standards: standards(5)strlen(3)