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Re: How to write own function to allocation a set of structures?

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On 03/20/12 07:58 PM, Martin De Kauwe wrote:
> Sorry I am not sure I quite sure I followed that. I do have variable
> length structures, e.g. some are X parameters long, some are a set of
> controlling flags. I tried implementing the first example, but I am
> clearly misunderstanding how to do this.
>
> in the .h file
>
> typedef struct {
>      FILE *ifp;
>      int num_days;
>      etc...
> } control_struct;
>
> void allocate_structure(structure **);
>
> in the .c file
>
> int main(int argc, char **argv)
> {
>      /* Allocate all structures */
>      control_struct *ctrl;
>      allocate_structure(&ctrl);
>      etc...
>
> void allocate_structure(structure **s)
> {
>      if ((*s = malloc(sizeof(*s))) == NULL) {
>          fprintf(stderr, "some msg\n");
>          exit(EXIT_FAILURE);
>      }
>
> }
>
> it says it doesn't know what 'structure' is when it compiles. I must
> be misunderstanding as this is what I didn't get, i.e. how to pass the
> structure, what you call it when you pass it to the function.

It sounds like you are looking for C++ style templates, which C lacks.

In C, you would have to resort to a macro.  Something like

#define ALLOCATE_STRUCTURE( s ) \
   if ((s = malloc(sizeof(*s))) == NULL) { \
     fprintf(stderr, "some msg\n"); \
     exit(EXIT_FAILURE); } \


-- 
Ian Collins

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Thread

How to write own function to allocation a set of structures? Martin De Kauwe <mdekauwe@gmail.com> - 2012-03-19 19:32 -0700
  Re: How to write own function to allocation a set of structures? Ian Collins <ian-news@hotmail.com> - 2012-03-20 15:50 +1300
  Re: How to write own function to allocation a set of structures? Barry Schwarz <schwarzb@dqel.com> - 2012-03-19 20:14 -0700
    Re: How to write own function to allocation a set of structures? Martin De Kauwe <mdekauwe@gmail.com> - 2012-03-19 23:58 -0700
      Re: How to write own function to allocation a set of structures? Ian Collins <ian-news@hotmail.com> - 2012-03-20 21:13 +1300
        Re: How to write own function to allocation a set of structures? Martin De Kauwe <mdekauwe@gmail.com> - 2012-03-20 02:32 -0700
      Re: How to write own function to allocation a set of structures? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-03-20 13:06 +0000
  Re: How to write own function to allocation a set of structures? ImpalerCore <jadill33@gmail.com> - 2012-03-20 07:27 -0700

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