Newsgroups: gnu.gcc.help,comp.parallel.mpi
From: "Mark S. Novojilov" <novojilo@explorer.uni-trier.de>
Subject: Re: Mixing data declarations with function calls
Organization: Universitaet Trier
Date: Fri, 19 Sep 1997 03:45:01 +0200
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Message-ID: <3421D91D.99CB2319@explorer.uni-trier.de>

Paul Bristow wrote:

> The following, trivial piece of MPI/C code compiles fine so long as I omit
> the line "int k;", however, if I leave it in I get the following:
>
> new.c: In function `main':
> new.c:21: parse error before `int'
> *** Error code 1
> make: Fatal error: Command failed for target `new'
>
> Unfortunately, I have a need to mix function calls and data declarations.
> MPI is using gcc as its C compiler.  My guess is that it is gcc enforcing
> good programing style rather than a problem with MPI.  Does anybody know?
> And more importantly if it is a 'feature' any ideas how I turn it off?

gcc is not inforcing good style, but inforcing correct C syntax.In C you
can't declare variables at any place you like, only
at the beginning of {...} block!  From the code below I don't
see why you need to declare k between fuction calls. Maybe I didn't
understand something. Declare k at the beginning of main, or
make a {} block around the scope of k, or use C++.

> Thanks,
>         Paul C Bristow.
>
> #include <stdio.h>
> #include <mpi.h>
> #define LIST_NO_BLOCKS 2
>
> typedef struct LNode *ListPtr;
>
> typedef struct LNode{
>   int Data;
>   ListPtr Next;
> }ListNode;
> typedef int DummyPtr;
>
> void main(int argc,char *argv[]){
>   int NoProcs,MyId;
>   MPI_Aint Extent;
>
>   int ArrayOfBlockLengths[LIST_NO_BLOCKS]={1,1};
>   MPI_Type_extent(MPI_INT,&Extent);
>
>   int k;
>   MPI_Init(&argc,&argv);
>   MPI_Comm_size(MPI_COMM_WORLD,&NoProcs);
>   MPI_Comm_rank(MPI_COMM_WORLD,&MyId);
>
>
>   MPI_Finalize();
>
> }