# What do these build warnings mean?

Whenever I build blender from source (2.8), I get a number of these build warnings. What do they really mean? And will it affect the performance of the built binary in anyway?

This warning stays on screen for a long time before the build proceeds and again stops on a similar warning with just the numbers updated. What do they mean?

# Compiler Warning (level 1) C4005

'identifier' : macro redefinition

The macro identifier is defined twice. The compiler uses the second macro definition.

In most of the programming language, warning often mean bad code structure that might let the compile process work in a bad situation. But most of the time it just indicate the programmer that there might be a better way to implement the code.

And in this warning (C4005). It is fine for any performance issue since the compile should handle it correctly by ignore it or replace it. And in the source code they should be the same value and it's a minor thing in my opinion.

Only if you try the build and find out there are something wrong, you should check back if there is some bug in source code. And most of the time those bug will raise an error and halt the compile process.

If you care about those thing, you can search those warning in google or something else. With the key word after your code path, e.g. warning integer conversion resulted in a change of sign