| Summary: | G4VPhysicalVolume: unsafe handling of rotation matrix for unrotated volumes | ||
|---|---|---|---|
| Product: | Geant4 | Reporter: | Nicola Mori <mori> |
| Component: | geometry/volumes | Assignee: | Gabriele Cosmo <Gabriele.Cosmo> |
| Status: | RESOLVED WONTFIX | ||
| Severity: | trivial | CC: | mori |
| Priority: | P5 | ||
| Version: | 10.0 | ||
| Hardware: | All | ||
| OS: | All | ||
|
Description
Nicola Mori
2014-07-11 15:47:47 CEST
Sorry, I posted before completing a sentence. Here's the complete report: In G4VPhysicalVolume::GetObjectRotation a pointer to the statically initialized identity matrix IdentityRM is returned for unrotated objects. However, the calling function might modify the static object pointed by the return pointer, so that a subsequent call to G4VPhysicalVolume::GetObjectRotation will return a non-identity matrix. The fact that &IdentityRM is returned as a non-const pointer does not generate an error at compile time since IdentityRM is not a member object of G4VPhysicalVolume. The const signature for the method is then uneffective in forbidding the modification of a static variable returned by address. This problem might be solved either by defining a non-static IdentityRM with a performance penalty or by changing the function signature to: const G4RotationMatrix* G4VPhysicalVolume::GetObjectRotation() const; with all the cons of an API break. The method GetObjectRotation() in G4VPhysicalVolume is in fact obsolete as reported in the declaration (the issue you mention are known and unfortunate, and your first suggested solution won't work as you cannot return the address of a non-static local object to the function...); the method is kept as is for backwards compatibility. The method GetObjectRotationValue() should be used instead. |