### _debug_strcpy -- Copy Strings

Format

>     #include <string.h>
>     char *_debug_strcpy(char *string1, const char *string2,
>                         const char *filename, size_t line);

Language Level: Extension
_debug_strcpy is the debug version of strcpy. Like strcpy, it copies string2, including the ending null character, to the location specified by string1.

_debug_strcpy validates the heap after copying the string to the target location, and performs this check only when the target is within a heap. _debug_strcpy makes an implicit call to _heap_check. If _debug_strcpy detects a corrupted heap when it makes a call to _heap_check, _debug_strcpy will report the file name file and line number line in a message.

Note: _debug_strcpy checks only the current default heap. Therefore, this debug support will not check all heaps within applications that have multiple user heaps.

To use _debug_strcpy, you must compile with the debug memory (/Tm) compiler option. This option maps all strncat calls to _debug_strcpy. You do not have to change your source code, in order for _debug_strcpy to verify the heap.

Note: The /Tm option maps all calls to other string functions and all calls to memory management functions (including a heap-specific version), to their debug counterparts. To prevent a call from being mapped, parenthesize the function name.

Return Value
_debug_strcpy returns a pointer to the copied string (string1).

Example
This example is similar to the strcpy example, except that it contains a programming error. The source string is too long for the destination buffer, and the strcpy operation damages the heap.

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

    #define  SIZE          10

    int main(void)
    {
       char *source = "1234567890123456789";
       char *destination;
       char *return_string;

       destination = (char*)malloc(SIZE);
       strcpy(destination, "abcdefg"),

       printf("destination is originally = '%s'\n", destination);
       return_string = strcpy(destination, source);
       printf("After strcpy, destination becomes '%s'\n\n", destination);
       return 0;

       /****************************************************************************
          The output should be similar to:

          destination is originally = 'abcdefg'
          End of allocated object 0x00073c80 was overwritten at 0x00073c8a.
          The first eight bytes of the memory block (in hex) are: 3132333435363738.
          This memory block was (re)allocated at line number 13 in strcpy.c.
          Heap state was valid at line 14 of strcpy.c.
          Memory error detected at line 17 of strcpy.c.
       ****************************************************************************/
    }

Managing Memory with Multiple Heaps

_debug_memcpy -- Copy Bytes
_debug_strncpy -- Copy Strings
_heap_check -- Validate Default Memory Heap
strcpy -- Copy Strings
strncpy -- Copy Strings
<string.h>
/Tm compiler option