Ticket #113 (closed defect: fixed)

Opened 10 months ago

Last modified 9 months ago

symbol clashes

Reported by: jasper Owned by: jasper
Priority: major Milestone: Maintenance of Phase II
Component: Demo PPM Version: 1.2.0.9
Keywords: Cc:

Description

On linux, a dynamic linker will only take into account public symbols once. So a symbol clash between two shared software components will cause the dynamic linker to mistake the functions of one for the other.

This has now been observed, without mitigation, the class "PropertyPackage?" in the test suite clashes with the class "PropertyPackage?" in the WaterPP, both of which export ICapeIdentification with identical symbol names. To the effect of the linker putting only one of them in the symbol table at runtime, and member functions of one class are invoked only, even if the other class is used. Which naturally leads to undefined behaviour (crash).

To mitigate, all components should by default hide their symbols from the dynamic linker, or alternatively use a namespace that is unique in the world. The former is the easier solution, and is obtained in CMake via this option

set(CMAKE_CXX_VISIBILITY_PRESET hidden)

Only the class factories need to be public, which is done automatically by COBIA's definition for COBIA_EXPORT:

#define COBIAEXPORT __attribute__((visibility("default")))

Change History

comment:1 Changed 10 months ago by jasper

  • Status changed from new to closed
  • Resolution set to fixed

COBIA itself already hid its symbols.

Fixed in revision 253 for COBIA Phase II

Fixed in revision 254 for COBIA Phase III

comment:2 Changed 9 months ago by michelpons

  • Milestone set to Maintenance of Phase II
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