astMemCachingastMemCaching - Controls whether allocated but unused memory is cached in this module

Description:
This function sets a flag indicating if allocated but unused memory should be cached or not. It also returns the original value of the flag.

If caching is switched on or off as a result of this call, then the current contents of the cache are discarded.

Note, each thread has a separate cache. Calling this function affects only the currently executing thread.

Synopsis:
int astMemCaching( int newval )
Parameters:
newval
The new value for the MemoryCaching tuning parameter (see astTuneastTune in objectc.c). If AST__TUNULL is supplied, the current value is left unchanged.
Returned Value:
astMemCaching()
The original value of the MemoryCaching tuning parameter.