Re: Bug with strcat

[Corinna Vinschen <corinna-cygwin at cygwin dot com>]

On Jul  5 10:11, Ivan Mari wrote:
> This code produces an access violation.

Yep, no wonder.
>  Commenting out the arr[] it works 
> fine. Leaving the arr[]  and commenting out the strcat works too.
> Anyway on a Linux with GCC 3.4.2 it works as it is presented here without 
> problems

Only coincidentally.

> #include <stdarg.h>
> #include <stdio.h>
> #include <stdlib.h>
> #include <string.h>
> 
> int main()
> {
> 
>        int arr[] = {1,2,3,4,5};
> 
>        char *buf = (char *) malloc (80);
         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
	 Using malloc does *not* initialize the allocated area to all zero.

>        if (buf == ((void *)0))
>                printf("LKD error: Not enough memory\n");
> 
>   		int a = 20;
> 
> 		{char tempBuffer[80];int bsize;snprintf (tempBuffer,80, 
                                     ^^^^^^^^^
				     uninitialized auto variable

> 		"Ivan %d", a );bsize += strlen(tempBuffer) + 1; buf = (char *) realloc 
                              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
			      adding a value to an uninitialized auto variable

> (buf, bsize); strcat(buf, tempBuffer);}
                ^^^^^^^^^^^^^^^^^^^^^^^
		Using strcat on an uninitialized buffer

> 
> return 0;
> }


Corinna

-- 
Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Project Co-Leader          mailto:cygwin@cygwin.com
Red Hat, Inc.

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