Externals and Memory Leaks???

[Dave]

Hi All,

I have a Stack that uses two functions from an external:

XGetData("myTempData")
XProcessData(myTempData,"myNewData")

XGetData() Gets the data into the correct format and stores it in the  
RunRev variable "myTempData".

XProcessData() takes the data in "myTempData", processes it and puts  
the results into "myNewData".

This all works well and produces good results, the only problem is  
that memory seems to be leaking by quite a lot and the two data  
buffers here are quite large.

In the external, I use malloc() to allocate the buffers and then use  
"SetVariableEx()" to pass it back to RunRev. My question is, who is  
responsible for freeing the data?

I am guessing that the on each subsequent call to the External  
Functions causes a new block to be allocated and overwrites the  
contents of the old RunRev "ExternalString" structure without first  
freeing it. How should I handle this? Do I need to check if the  
variable passed into my external already has data allocated and if so  
either free or re-use the data (the block sizes are likely to be the  
same).

Any advice or help on this greatly appreciated.

All the Best
Dave

PS

I set the External Variable using the following function:


OSStatus LTWLibraryUtilsSetExternalVariablePtr(	char*				 
theVariableNamePtr,
												const char*			theVariablePtr,
												long				theVariableSize)
{
ExternalString				myExternalVariableInfo;
int							myRunRevStatus;

//**
//**	Get the External Variable
//**
myExternalVariableInfo.buffer = theVariablePtr;
myExternalVariableInfo.length = theVariableSize;
SetVariableEx 
(theVariableNamePtr,"",&myExternalVariableInfo,&myRunRevStatus);
if (myRunRevStatus == EXTERNAL_FAILURE)
	return(kRunRevVariableNotDefined);
	
//**
//**	Good Return
//**
return(noErr);
}