[petsc-users] using petsc functions in structs?

[Jed Brown]

On Wed, 12 May 2010 15:54:42 -0400, John-Michael Fischer <fischej at umich.edu> wrote:
> Hi, I'm fighting this issue.
> 
> In the follow code which is macro for a struct divide I get three errors about casting PetscErrorCode types into the name of the struct.
> 
> This is the code
> struct IMPACT_Moment Divide(struct IMPACT_Moment * M1, struct IMPACT_Moment * M3)
> {  // does M1./M3 and returns M2
>   PetscErrorCode ierr;
>   struct IMPACT_Moment M2;
>   M2.Nx = M1->Nx;
>   M2.Ny = M1->Ny;
>   M2.coords[0] = M1->coords[0];
>   M2.coords[1] = M1->coords[1];
> 
> 78:  ierr = VecCopy(M1->xaxis, M2.xaxis);CHKERRQ(ierr);
> 79:  ierr = VecCopy(M1->yaxis, M2.yaxis);CHKERRQ(ierr);
> 
> 81:  ierr = MatCopy(M1->values, M2.values, DIFFERENT_NONZERO_PATTERN);CHKERRQ(ierr);
> ...... goes on
> 
> 
> and these are the only three error messages I get
> 
> IMPACTA_Moments.h: In function ‘IMPACT_Moment Divide(IMPACT_Moment*, IMPACT_Moment*)’:
> IMPACTA_Moments.h:78: error: conversion from ‘PetscErrorCode’ to non-scalar type ‘IMPACT_Moment’ requested
> IMPACTA_Moments.h:79: error: conversion from ‘PetscErrorCode’ to non-scalar type ‘IMPACT_Moment’ requested
> IMPACTA_Moments.h:81: error: conversion from ‘PetscErrorCode’ to non-scalar type ‘IMPACT_Moment’ requested

The CHKERRQ macro expects that the enclosing function returns
PetscErrorCode.  Because your code has to handle errors somehow, your
functions should either return PetscErrorCode (int) or you should use
CHKERRXX and C++ exceptions (if you are writing C++ and prefer to use
exceptions).

Jed