C - String String Copying

Introduction

strcpy_s() function copies the contents of one string variable to another.

The first argument identifies the destination for the copy
The second argument is an integer specifying the size of the first argument
The third argument is the source string.

Here's an example:

char source[] = "test test test.";
char destination[50];
if(strcpy_s(destination, sizeof(destination), source))
  printf("An error occurred copying the string.\n");

The condition of if statement is an expression that calls strcpy_s() to copy the contents of the source array.

The value of the expression is the value returned by strcpy_s().

This will be 0 if the copy works and nonzero if it doesn't.

A nonzero integer value corresponds to true, the printf() call will be executed to output an error message.

strncpy_s() function can copy part of the source string to the destination.

The first three arguments are the same as for strcpy_s(), and the fourth argument specifies the maximum number of characters to be copied.

If a \0 is found in the source string before the maximum specified characters have been copied, copying ceases and the \0 is appended to the destination.


char source[] = "this is a test test test test test test.";
char destination[50];
if(strncpy_s(destination, sizeof(destination), source, 17))
  printf("An error occurred copying the string.\n");