Re: Reading strings

[Philip Sheard]

>  VoidHand sh;
>  CharPtr s;
>
>  sh = MemHandleNew(SIZE);
>  fetch(s,sh);
>  // Now s is garbage and anything that uses it crashes
>
> }
>
> void fetch(CharPtr s, VoidHand sh)
> {
>  s = MemHandleLock(sh);
>  StrCopy(s,"custard");
>  MemHandleUnlock(sh);

The problem is that s itself is never getting set in the main segment,
because the value you pass in to fetch is not returned.

solution 1: pass a pointer to s:

  VoidHand sh;
  CharPtr s;

  sh = MemHandleNew(SIZE);
  fetch(&s,sh);

void fetch(CharPtr *s, VoidHand sh)
{
  *s = MemHandleLock(sh);
  StrCopy(*s,"custard");
  MemHandleUnlock(sh);
}

solution 2: lock sh before calling fetch:

  VoidHand sh;
  CharPtr s;

  sh = MemHandleNew(SIZE);
  s = MemHandleLock(sh);
  fetch(s,sh);

void fetch(CharPtr s, VoidHand sh)
{
  StrCopy(s,"custard");
  MemHandleUnlock(sh);
}




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