astTuneastTune
-
Set or get an integer-valued AST global tuning parameter
- Description:
- This function returns the current value of an integer-valued AST
global tuning parameter, optionally storing a new value for the
parameter. For character-valued tuning parameters, see
astTuneCastTuneC.
- Synopsis:
- int astTune( const char
name, int value )
- Parameters:
-
name
-
The name of the tuning parameter (case-insensitive).
-
value
-
The new value for the tuning parameter. If this is AST__TUNULL,
the existing current value will be retained.
- Returned Value:
-
astTune()
-
The original value of the tuning parameter. A default value will
be returned if no value has been set for the parameter.
- Notes:
- This function attempts to execute even if the AST error
status is set
on entry, although no further error report will be
made if it subsequently fails under these circumstances.
- All threads in a process share the same AST tuning parameters
values.
-
Tuning Parameters
:
-
-
ObjectCaching
-
A boolean flag which indicates what should happen
to the memory occupied by an AST ObjectObject when the Object is deleted
(i.e. when its reference count falls to zero or it is deleted using
astDeleteastDelete).
If this is zero, the memory is simply freed using the systems "free"
function. If it is non-zero, the memory is not freed. Instead a
pointer to it is stored in a pool of such pointers, all of which
refer to allocated but currently unused blocks of memory. This allows
AST to speed up subsequent Object creation by re-using previously
allocated memory blocks rather than allocating new memory using the
systems malloc function. The default value for this parameter is
zero. Setting it to a non-zero value will result in Object memory
being cached in future. Setting it back to zero causes any memory
blocks currently in the pool to be freed. Note, this tuning parameter
only controls the caching of memory used to store AST Objects. To
cache other memory blocks allocated by AST, use MemoryCaching.
-
MemoryCaching
-
A boolean flag similar to ObjectCaching except
that it controls caching of all memory blocks of less than 300 bytes
allocated by AST (whether for internal or external use), not just
memory used to store AST Objects.