🚀 go-pugleaf

In article <1992Jul25.163852.19770@uwm.edu> rca@csd4.csd.uwm.edu (Robert C Allender) writes:
> [character array mysteriously gets trashed]
>
>main() {
>  char drive, *c;
>    :
>  c = scrollbox(drive,61,10);  <---- This gets a directory, etc. 
>    :
>  list_dir(c);                   <-- by this point the array values are GONE.

I strongly suspect that "c = scrollbox(...);" is the culprit.  scrollbox()
is returning a pointer to a character array, but where did this array
come from?  Does scrollbox look like this:?

	char *
	scrollbox(...)
	{
		char	array[80] ;

		blahblah ;

		return array ;
	}

If so, there's your problem.  "array" is allocated on the fly from the
stack when scrollbox() is entered.  When scrollbox() becomes free again,
"array" is returned to free space and a pointer to it is now a pointer
to gibberish.  The array contains the valid data for awhile, but the
first function to come along and re-use that stack space will trash
it.  Instead, you should do:

	char *
	scrollbox(...)
	{
		static char array[80] ;

		blahblah ;

		return array ;
	}

or

	char *
	scrollbox(...)
	{
		char *array = malloc(80) ;

		blahblah ;

		return array ;
	}

		-ed falk, sun microsystems
		 sun!falk, falk@sun.com
	terrorist, cryptography, DES, drugs, cipher, secret, decode,
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