From:	naisbodo <naisbodo AT enteract DOT com>
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: Help! function typedef
Date:	12 Dec 2000 00:45:44 GMT
Lines:	43
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To:	djgpp AT delorie DOT com
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Reply-To:	djgpp AT delorie DOT com

[Attribution lost] wrote:
>> > NO NO NO. I wrote:
>> > typedef int (MY_FUNC_TYPE)(void);
>> > 
>> > MY_FUNC func
>> >  {
>> >   return 0;
>> >  }

The valid C he might be thinking of is as follows:

    typedef int MY_FUNC_TYPE(void);
    MY_FUNC_TYPE func;

The C standard gives examples of this kind of typedef to make function
parameters more clear in 6.7.7#7:

       [#7] EXAMPLE 4 On the other hand, typedef names can be  used
       to  improve  code  readability.   All three of the following
       declarations of the signal function specify exactly the same
       type, the first without making use of any typedef names.

               typedef void fv(int), (*pfv)(int);

               void (*signal(int, void (*)(int)))(int);
               fv *signal(int, fv *);
               pfv signal(int, pfv);

Actually declaring functions in this manner is less useful, because you 
can *only* declare (and prototype) a function with the above; you can't
define one, hence Nate's common macro workaround given below:

Nate Eldredge <neldredge AT hmc DOT edu> wrote:
> #define DECLARE_MY_FUNC(name) int name (void)

It is often accompanied by a typedef for a function to the same type, 
in my experience:

    #define DECLARE_MY_FUNC(name) int name(void)
    typedef int my_func_t(void);

-- 
naisbodo AT enteract DOT com

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