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Groups > comp.lang.c > #139440
| From | "Pascal J. Bourguignon" <pjb@informatimago.com> |
|---|---|
| Newsgroups | comp.lang.c |
| Subject | Re: calling argumentless function with argument |
| Date | 2019-01-05 16:11 +0100 |
| Organization | Informatimago |
| Message-ID | <m2y37zkulv.fsf@despina.home> (permalink) |
| References | <g99egeFi15cU1@mid.uni-berlin.de> <g9bp36F2osvU1@mid.uni-berlin.de> |
jt@toerring.de (Jens Thoms Toerring) writes:
> Unfortunately, for historical reasons some of these func-
> tions accept a pointer, while others accept no argument.
> To minimize the amount of work to implement this and lower
> the bar to adopting the new system, it would be helpful if
> the existing functions could be used without modifications.
> For that being able to call a function that does not accept
> arguments with an argument could be quite nice. As it stands
> we have to change all these functions to accept an argument
> that's ignored anyway, and to hunt down all other calls of
> the functions and add a basically useless argument to all
> of them.
#include <stdlib.h>
#include <stdio.h>
void foo(void);
void bar(void);
void quux(void*);
void baz(void*);
typedef void (*void_fun)(void);
typedef void (*pointer_fun)(void*);
typedef struct {
enum { f_void, f_pointer } type;
union {
void_fun f_void_fun;
pointer_fun f_pointer_fun;
} fun;
} typed_fun;
void call(typed_fun* fun){
switch(fun->type){
case f_void: fun->fun.f_void_fun(); break;
case f_pointer: fun->fun.f_pointer_fun(NULL); break;}}
typed_fun funs[]={
{ .type=f_void, .fun.f_void_fun=foo },
{ .type=f_void, .fun.f_void_fun=bar },
{ .type=f_pointer, .fun.f_pointer_fun=quux },
{ .type=f_pointer, .fun.f_pointer_fun=baz }};
#define countof(a) (sizeof(a)/(sizeof(a[0])))
int main(){
for(int i=0;i<countof(funs);i++){
call(&funs[i]);}
return 0;}
void foo(void){printf("%s()\n",__FUNCTION__);}
void bar(void){printf("%s()\n",__FUNCTION__);}
void quux(void*arg){printf("%s(%p)\n",__FUNCTION__,arg);}
void baz(void*arg){printf("%s(%p)\n",__FUNCTION__,arg);}
/*
-*- mode: compilation; default-directory: "/tmp/" -*-
Compilation started at Sat Jan 5 16:10:03
SRC="/tmp/f.c" ; EXE="f" ; gcc -I. -L. -g3 -ggdb3 -o ${EXE} ${SRC} && ./${EXE} && echo status = $?
foo()
bar()
quux(0x0)
baz(0x0)
status = 0
Compilation finished at Sat Jan 5 16:10:03
*/
> Of course, this isn't just about energy meters, there
> are quite a number of other subsystems where it would be
> better if "events" could be raised and then dealt with
> by a central instance, distributing the information
> to all subsystems that have registered their interest.
Also, note that if you need to pass a specific pointer to the function,
you can also add it to the typed_fun structure and use it in call().
--
__Pascal J. Bourguignon__
http://www.informatimago.com
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calling argumentless function with argument jt@toerring.de (Jens Thoms Toerring) - 2019-01-04 16:04 +0000
Re: calling argumentless function with argument David Brown <david.brown@hesbynett.no> - 2019-01-04 17:34 +0100
Re: calling argumentless function with argument Bart <bc@freeuk.com> - 2019-01-04 17:30 +0000
Re: calling argumentless function with argument fir <profesor.fir@gmail.com> - 2019-01-04 09:50 -0800
Re: calling argumentless function with argument fir <profesor.fir@gmail.com> - 2019-01-05 05:58 -0800
Re: calling argumentless function with argument fir <profesor.fir@gmail.com> - 2019-01-05 07:56 -0800
Re: calling argumentless function with argument fir <profesor.fir@gmail.com> - 2019-01-05 10:56 -0800
Re: calling argumentless function with argument fir <profesor.fir@gmail.com> - 2019-01-05 14:55 -0800
Re: calling argumentless function with argument "Pascal J. Bourguignon" <pjb@informatimago.com> - 2019-01-06 01:29 +0100
Re: calling argumentless function with argument Bart <bc@freeuk.com> - 2019-01-06 02:20 +0000
Re: calling argumentless function with argument Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-01-06 02:51 +0000
Re: calling argumentless function with argument "Pascal J. Bourguignon" <pjb@informatimago.com> - 2019-01-06 12:12 +0100
Re: calling argumentless function with argument Bart <bc@freeuk.com> - 2019-01-06 11:53 +0000
Re: calling argumentless function with argument "Pascal J. Bourguignon" <pjb@informatimago.com> - 2019-01-06 12:58 +0100
Re: calling argumentless function with argument Bart <bc@freeuk.com> - 2019-01-06 11:45 +0000
Re: calling argumentless function with argument "Pascal J. Bourguignon" <pjb@informatimago.com> - 2019-01-06 12:58 +0100
Re: calling argumentless function with argument Bart <bc@freeuk.com> - 2019-01-06 12:24 +0000
Re: calling argumentless function with argument Keith Thompson <kst-u@mib.org> - 2019-01-06 04:34 -0800
Re: calling argumentless function with argument "Pascal J. Bourguignon" <pjb@informatimago.com> - 2019-01-06 13:41 +0100
Re: calling argumentless function with argument fir <profesor.fir@gmail.com> - 2019-01-06 04:10 -0800
Re: calling argumentless function with argument "Pascal J. Bourguignon" <pjb@informatimago.com> - 2019-01-06 13:51 +0100
Re: calling argumentless function with argument "Pascal J. Bourguignon" <pjb@informatimago.com> - 2019-01-06 13:56 +0100
Re: calling argumentless function with argument fir <profesor.fir@gmail.com> - 2019-01-06 05:20 -0800
Re: calling argumentless function with argument "Pascal J. Bourguignon" <pjb@informatimago.com> - 2019-01-06 16:08 +0100
Re: calling argumentless function with argument Keith Thompson <kst-u@mib.org> - 2019-01-06 15:59 -0800
Re: calling argumentless function with argument Bart <bc@freeuk.com> - 2019-01-06 13:42 +0000
Re: calling argumentless function with argument fir <profesor.fir@gmail.com> - 2019-01-06 06:22 -0800
Re: calling argumentless function with argument "Pascal J. Bourguignon" <pjb@informatimago.com> - 2019-01-06 16:19 +0100
Re: calling argumentless function with argument fir <profesor.fir@gmail.com> - 2019-01-06 07:42 -0800
Re: calling argumentless function with argument fir <profesor.fir@gmail.com> - 2019-01-06 08:05 -0800
Re: calling argumentless function with argument fir <profesor.fir@gmail.com> - 2019-01-06 08:30 -0800
Re: calling argumentless function with argument "Pascal J. Bourguignon" <pjb@informatimago.com> - 2019-01-06 17:44 +0100
Re: calling argumentless function with argument fir <profesor.fir@gmail.com> - 2019-01-06 08:54 -0800
Re: calling argumentless function with argument fir <profesor.fir@gmail.com> - 2019-01-07 08:02 -0800
Re: calling argumentless function with argument fir <profesor.fir@gmail.com> - 2019-01-07 08:07 -0800
Re: calling argumentless function with argument fir <profesor.fir@gmail.com> - 2019-01-07 09:16 -0800
Re: calling argumentless function with argument fir <profesor.fir@gmail.com> - 2019-01-07 09:40 -0800
Re: calling argumentless function with argument fir <profesor.fir@gmail.com> - 2019-01-07 09:57 -0800
Re: calling argumentless function with argument fir <profesor.fir@gmail.com> - 2019-01-09 02:23 -0800
Re: calling argumentless function with argument "Pascal J. Bourguignon" <pjb@informatimago.com> - 2019-01-06 16:17 +0100
Re: calling argumentless function with argument Bart <bc@freeuk.com> - 2019-01-06 16:56 +0000
Re: calling argumentless function with argument fir <profesor.fir@gmail.com> - 2019-01-06 09:12 -0800
Re: calling argumentless function with argument fir <profesor.fir@gmail.com> - 2019-01-06 12:39 -0800
Re: calling argumentless function with argument "Pascal J. Bourguignon" <pjb@informatimago.com> - 2019-01-06 18:26 +0100
Re: calling argumentless function with argument Bart <bc@freeuk.com> - 2019-01-06 18:52 +0000
Re: calling argumentless function with argument fir <profesor.fir@gmail.com> - 2019-01-06 02:32 -0800
Re: calling argumentless function with argument Keith Thompson <kst-u@mib.org> - 2019-01-06 04:38 -0800
Re: calling argumentless function with argument "Pascal J. Bourguignon" <pjb@informatimago.com> - 2019-01-06 13:42 +0100
Re: calling argumentless function with argument Robert Wessel <robertwessel2@yahoo.com> - 2019-01-06 10:27 -0600
Re: calling argumentless function with argument "Pascal J. Bourguignon" <pjb@informatimago.com> - 2019-01-06 17:47 +0100
Re: calling argumentless function with argument David Brown <david.brown@hesbynett.no> - 2019-01-04 19:30 +0100
Re: calling argumentless function with argument Keith Thompson <kst-u@mib.org> - 2019-01-04 10:55 -0800
Re: calling argumentless function with argument Robert Wessel <robertwessel2@yahoo.com> - 2019-01-05 00:16 -0600
Re: calling argumentless function with argument queequeg@trust.no1 (Queequeg) - 2019-01-07 10:43 +0000
Re: calling argumentless function with argument Robert Wessel <robertwessel2@yahoo.com> - 2019-01-07 16:25 -0600
Re: calling argumentless function with argument Barry Schwarz <schwarzb@dqel.com> - 2019-01-04 09:54 -0800
Re: calling argumentless function with argument Thiago Adams <thiago.adams@gmail.com> - 2019-01-04 10:26 -0800
Re: calling argumentless function with argument Keith Thompson <kst-u@mib.org> - 2019-01-04 12:07 -0800
Re: calling argumentless function with argument James Kuyper <jameskuyper@alumni.caltech.edu> - 2019-01-04 15:03 -0500
Re: calling argumentless function with argument Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-01-05 00:04 +0000
Re: calling argumentless function with argument James Kuyper <jameskuyper@alumni.caltech.edu> - 2019-01-05 22:36 -0500
Re: calling argumentless function with argument jt@toerring.de (Jens Thoms Toerring) - 2019-01-05 13:17 +0000
Re: calling argumentless function with argument fir <profesor.fir@gmail.com> - 2019-01-05 06:06 -0800
Re: calling argumentless function with argument David Brown <david.brown@hesbynett.no> - 2019-01-05 15:42 +0100
Re: calling argumentless function with argument Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-01-05 14:58 +0000
Re: calling argumentless function with argument "Pascal J. Bourguignon" <pjb@informatimago.com> - 2019-01-05 16:11 +0100
Re: calling argumentless function with argument Richard Damon <Richard@Damon-Family.org> - 2019-01-05 11:23 -0500
Re: calling argumentless function with argument Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-01-05 16:53 +0000
Re: calling argumentless function with argument Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-01-06 00:46 +0000
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