:orphan:
# PetscCallCXX
Checks C++ function calls and if they throw an exception, catch it and then return a PETSc error code 
## Synopsis
```
#include <petscerror.h>
void PetscCallCXX(...) noexcept;
```
Not Collective


## Input Parameter

- ***__VA_ARGS__ -*** An arbitrary expression





## Notes
`PetscCallCXX(...)` is a macro replacement for
```none
  try {
    __VA_ARGS__;
  } catch (const std::exception& e) {
    return ConvertToPetscErrorCode(e);
  }
```

Due to the fact that it catches any (reasonable) exception, it is essentially noexcept.

If you cannot return a `PetscErrorCode` use `PetscCallCXXAbort()` instead.


## Example Usage
```none
  void foo(void) { throw std::runtime_error("error"); }

  void bar()
  {
    PetscCallCXX(foo()); // ERROR bar() does not return PetscErrorCode
  }

  PetscErrorCode baz()
  {
    PetscCallCXX(foo()); // OK

    PetscCallCXX(
      bar();
      foo(); // OK multiple statements allowed
    );
  }

  struct bop
  {
    bop()
    {
      PetscCallCXX(foo()); // ERROR returns PetscErrorCode, cannot be used in constructors
    }
  };

  // ERROR contains do-while, cannot be used as function-try block
  PetscErrorCode qux() PetscCallCXX(
    bar();
    baz();
    foo();
    return 0;
  )
```



## See Also
 `PetscCallCXXAbort()`, `PetscCallThrow()`, `SETERRQ()`, `PetscCall()`,
`SETERRABORT()`, `PetscCallAbort()`, `PetscTraceBackErrorHandler()`, `PetscPushErrorHandler()`,
`PetscError()`, `CHKMEMQ`

## Level
beginner

## Location
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/include/petscerror.h.html#PetscCallCXX">include/petscerror.h</A>

## Examples
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/snes/tutorials/ex55k.kokkos.cxx.html">src/snes/tutorials/ex55k.kokkos.cxx</A><BR>


---
[Edit on GitLab](https://gitlab.com/petsc/petsc/-/edit/release/include/petscerror.h)


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