• Tyro (18/18) Sep 05 2006 Could someone please tell me if I'm reading the following correctly
• xs0 (8/20) Sep 05 2006 It's not being dereferenced, the * just means allocF is a pointer (to a
• Stewart Gordon (21/29) Sep 05 2006 Yes.

Tyro <ridimz yahoo.com> writes:

Could someone please tell me if I'm reading the following correctly

	int myfunc(MyStruct *ms, void * (*allocF)(size_t s))

The second parameter above [void * (*allocF)(size_t s)], is a pointer to 
a function that accepts a size_t parameter and returns a void pointer? 
If so, I have two questions:

	1) Why is the function  pointed to being dereferenced? Why [(*allocF)] 
instead of [(allocF)]?

	2) Is [void function(size_t s) allocF] a suitable replacement or would 
it be better to use a delegate?

Thanks
-- 
Andrew C. Edwards
-----------------------------------------------------
The truth we call D, has passed through three stages:
   First ridiculed; Then violently opposed;
   And now, it is being accepted as self-evident.
Consequently:
   C/C++ is rapidly approaching Stage 5 (being forgotten)!

xs0 <xs0 xs0.com> writes:

Tyro wrote:
 Could someone please tell me if I'm reading the following correctly
 
     int myfunc(MyStruct *ms, void * (*allocF)(size_t s))
 
 The second parameter above [void * (*allocF)(size_t s)], is a pointer to 
 a function that accepts a size_t parameter and returns a void pointer? 
 If so, I have two questions:
 
     1) Why is the function  pointed to being dereferenced? Why 
 [(*allocF)] instead of [(allocF)]?

It's not being dereferenced, the * just means allocF is a pointer (to a 
function). It's in parentheses because it would otherwise get parsed as 
a function returning void** (as opposed to a function _pointer_ 
returning void*), which is illegal as a parameter, afaik.

     2) Is [void function(size_t s) allocF] a suitable replacement or 
 would it be better to use a delegate?

Depends :) If myfunc is a C function, you have to use a function; if 
it's a D function, it's usually better to use a delegate..


xs0

Stewart Gordon <smjg_1998 yahoo.com> writes:

Tyro wrote:
 Could someone please tell me if I'm reading the following correctly
 
     int myfunc(MyStruct *ms, void * (*allocF)(size_t s))
 
 The second parameter above [void * (*allocF)(size_t s)], is a pointer to 
 a function that accepts a size_t parameter and returns a void pointer? 

Yes.

<snip>
     2) Is [void function(size_t s) allocF] a suitable replacement

No.  However, this is:

     int myfunc(MyStruct* ms, void* function(size_t s) allocF)

I always use the D function/delegate notation.  Much easier to read than 
the C notation.  Note also that the '*' has been attached to the type, 
which is more logical in D.

 or would it be better to use a delegate?

Whether you should use function or delegate depends on what you're going 
to pass in.

function - module level functions or static member functions
delegate - member functions acting on a specific object, or nested functions

Stewart.

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