Free-ing pointers returned from shared libraries compiled with different compiler

[paulushendrata]

Hi, I am new to C++ and UNIX programming!

I have a question. Is it safe for me to free a pointer returned by a library compiled using a different compiler? If so, why is the case?
My system is x86_64 Ubuntu 16.04, and the library was compiled using GCC 6, whereas my program is compiled using clang 3.8.

P.S.: the library is XCB (X11 C Binding). It returned pointers to data structures, but expect the app to free the pointers. The problem is that the library doesn't provide any 'free' function.

[paulushendrata]

What about "new"/"delete"? Does the actual implementation differs between compilers?

[raschupkin]

It happens sometimes that memory allocations and frees of different compilers are incompatible, but on Linux there should be no such problems, especially between gcc and clang.

[kbw]

Is it safe for me to free a pointer returned by a library compiled using a different compiler?

Probably not.

What about "new"/"delete"?

new/delete do their thing, i.e. allocate/release memory and call constructor/destructor. That isn't the problem.

The problem is making sure they're using the same heap.

Typically, this can be resolve using methods in the library, like create/release. I posted an example in this forum some time back. I'll see if I can find it.

EDIT:
http://www.cplusplus.com/forum/general/33662/

You need a release() method with these examples.
http://www.cplusplus.com/forum/general/35380/
http://www.cplusplus.com/forum/unices/184342/