strlen(3) Library Functions Manual strlen(3)
NAME
strlen - Finds the length of a string
LIBRARY
Standard C Library (libc.so, libc.a)
SYNOPSIS
#include <string.h>
size_t strlen( const char *s);
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
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.
Current industry standards specify that no value be reserved to indicate an error.
RELATED INFORMATION
Functions: string(3), uswitch(2), wcslen(3)
Standards: standards(5) delim off
strlen(3)