tree 28c74e6b47a0db7e0dc84cc58f5606c0a8747f02
parent 68e228944e2da1b3702c6d64b01f559c8b8b91f1
author Eric Fiselier <eric@efcs.ca> 1521661645 -0600
committer Eric Fiselier <eric@efcs.ca> 1521661645 -0600

Fix #552 - GCC and Clang warn on possibly invalid offsetof usage.

This patch disables the -Winvalid-offsetof warning for GCC and Clang
when using it to check the cache lines of the State object.

Technically this usage of offsetof is undefined behavior until C++17.
However, all major compilers support this application as an extension,
as demonstrated by the passing static assert (If a compiler encounters UB
during evaluation of a constant expression, that UB must be diagnosed).
Unfortunately, Clang and GCC also produce a warning about it.

This patch temporarily suppresses the warning using #pragma's in the
source file (instead of globally suppressing the warning in the build systems).
This way the warning is ignored for both CMake and Bazel builds without
having to modify either build system.