strlen

strlen

Compute Length of Null-Terminated String

Portability: ISO/ANSI C conforming, UNIX compatible

SYNOPSIS
DESCRIPTION
RETURN VALUE
CAUTION
PORTABILITY
IMPLEMENTATION
EXAMPLE
RELATED FUNCTIONS
SEE ALSO

SYNOPSIS

#include <string.h>

size_t strlen(const char *str);

DESCRIPTION

strlen returns the length of a null-terminated character string str .

RETURN VALUE

The return value is the length of the string, not counting the terminating null.

CAUTION

The scan for a null character continues until one is found, or until a protection or addressing exception occurs.

PORTABILITY

Note that many implementations before ANSI C define strlen to return int rather than size_t .

IMPLEMENTATION

If <string.h> is included (by an #include statement) and strlen is not undefined (by an #undef statement), strlen generates inline code. If the argument to strlen is a constant, the length is evaluated during compilation, and no code is generated for the function.

EXAMPLE

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

#define MAXLINE 100

main()
{
   char line[MAXLINE+1];

   puts("Enter some text (at least 2 characters):");
   gets(line);
   puts("The last half of your text is:");
   puts(line + (strlen(line)/2));
}

RELATED FUNCTIONS

mblen

SEE ALSO

String Utility Functions

Chapter Contents
Previous
Next
Top of Page