ABI 4?

[Kenneth F. Cunningham]

On 2018-03-25, at 10:30 AM, Michael wrote:

> Can someone give me a quick description of ABI 4 versus ABI 5? Google gives me a document about plants.
> 

Caveats:

1. I'm not an expert on this.
2. There are experts who might read this and may shame me.


My Understanding:

Most of it comes from here <https://gcc.gnu.org/onlinedocs/gcc-5.2.0/libstdc++/manual/manual/using_dual_abi.html>.

To fully comply with the c++11 standard, two library calls (copy-on-write strings, and std::list) had to be changed in a way that was incompatible with the older ABI 4 version. A number of other library calls use these two calls, so a number of other library calls are affected. 

To make this work, the namespace was changed. This generates errors on linking if you try to mix libraries (we've all seen those). This might possibly generate something that could link correctly, but still break on use (I've never seen that happen).

That's it.

Best,

Ken