[fpc-pascal] Memory leaks in FPC 2.3.1 SVN 13188

[Jonas Maebe]

On 25 May 2009, at 07:38, Bruce Tulloch wrote:

> Are we correct to assume that as soon as no variable in our program,  
> be
> it global, static, object field or property, refers to a dynamic  
> array,
> the dynamic array will be released. Are we also correct to assume that
> the reassignment of any variable referring to a dynamic array to a new
> value will cause the previous array value to be released (presuming
> nothing else refers to this array)?

Yes.

One caveat is that the memory may not be immediately released after  
the last reference that you know of disappears, because there may  
still be temporary memory locations (implicitly created by the  
compiler while evaluating expressions) containing a reference. Such  
temporary locations will be finalised either when they are reused by  
the compiler later on, or when the function in which they were created  
by the compiler exits (such temporary locations can never survive the  
scope in which they were created by the compiler).

However, this could only cause the behaviour you are seeing if you  
were to call halt() somewhere in a deeply nested function and some  
temporary locations in a parent stack frame still contained  
references, or of you call halt() while some threads are still running  
that have local variables/temporaries that point to such variables.


Jonas