Release mode static library much larger than debug mode version

Question

today i found out that the compiled static library i\'m working on is much larger in Release mode than in Debug. I found it very surprising

Answer 1

The optimization could be the issue here, notably automatically created inline functions will be bigger but faster in release than debug.

Answer 2

Personally I've never seen a release PDB be larger than a debug PDB. Same deal for LIBs.

Answer 3

The difference is specifically because of link-time code generation. Read the chapter Link-Time Code Generation in Compilers - What Every Programmer Should Know About Compiler Optimizations on MSDN - it basically says that with LTCG turned on the compiler produces much more data that is packed into the static library so that the linker can use that extra data for generating better machine code while actually linking the executable file.

Since you have LTCG off in Debug configuration the produced library is noticeably smaller since it doesn't have that extra data.

PS: Original Link (not working at 11/09/2015)