pthom / cibuildwheel_abi_study

Analyse ABI used by cibuildwheel vs pip install

I observed that when building a wheel from C++ sources on ubuntu 22.04, cibuildwheel will use the "GNU/Linux" ABI, when pip install will use SYSV (the older ABI).

sizeof(std::string) yields different results in those two context.

Is that something of importance?

A wheel built with pip install:

• uses the SYSV ABI (older set of conventions for system calls, object files, and libraries)
• sizeof(string)=8
• is linked against libstdc++.so.6

> file _mylib.cpython-310-x86_64-linux-gnu.so
 ELF 64-bit LSB shared object, x86-64, version 1 (SYSV), dynamically linked

A wheel built with cibuildwheel

• uses the GNU/Linux ABI (newer conventions for system calls, with modifications made by the GNU project)
• sizeof(string)=32
• is linked against libstdc++.so.6

> file _mylib.cpython-310-x86_64-linux-gnu.so
 ELF 64-bit LSB shared object, x86-64, version 1 (GNU/Linux), dynamically linked