Post the full rebuild log.
Can you use depends.exe to inspect your dll?
Do you see the function?
My guess is that C++ name mangling is causing you the trouble.
Sorry I somehow missed the reply to the post.
The full build log is:
-------------- Build: Debug in test (compiler: GNU GCC Compiler)---------------
mingw32-g++.exe -Wall -DBUILD_DLL -g -c "C:\Users\Owner\Desktop\Header Test\test\main.cpp" -o obj\Debug\main.o
mingw32-g++.exe -shared -Wl,--output-def=bin\Debug\libtest.def -Wl,--out-implib=bin\Debug\libtest.a -Wl,--dll obj\Debug\main.o -o bin\Debug\test.dll -luser32
Output file is bin\Debug\test.dll with size 35.87 KB
Process terminated with status 0 (0 minute(s), 0 second(s))
0 error(s), 0 warning(s) (0 minute(s), 0 second(s))
When I try to use dependency walker I get an error: At least one required implicit or forwarded dependency was not found, and a warning: At least one delay-load dependency module was not found. The problem with that is every API-MS_WIN_CORE dll gives an error.