HP C/iX Library Reference Manual (30026-90004)

Chapter 5 341

HP C/iX Library Function Descriptions

strlen

Computes the length of the string pointed to by

Syntax

#include <string.h>

size_t strlen(const char *

);

Parameters

A pointer to the character string.

Return Values

x The length of the string speciﬁed as an unsigned integer.

Description

In the strlen function,

is a character pointer to the null-terminated string to be

scanned. strlen() counts up to, but not including, the terminating null character. The

length of a string containing only a null character is zero.

NOTE

Since the value returned by strlen() is an unsigned number, care must be

taken when performing subtraction operations on the value returned by the

function. The following code fragment is incorrect:

…

for (i=0;i<=strlen(string)-1;i++

…

The string length of a null string minus one (strlen(string)-1) is a very

large positive number, not minus one (-1) as was intended. Thus, the code

above does not bypass the for loop, but erroneously executes the loop a large

number of times.

Example

len = strlen(string);

The integer len contains the total number of non-null characters in the string pointed to

by string. Thus,

string[len]

is the terminating null in string.