So I have been following this setup tutorial: http://www.programmersranch.com/2013/08/sdl2-setting-up-sdl2-in-visual-studio.html
And after attempting to build my project I get the following error:
1>------ Build started: Project: test, Configuration: Debug Win32 ------
1>MSVCRTD.lib(cinitexe.obj) : warning LNK4098: defaultlib 'msvcrt.lib' conflicts with use of other libs; use /NODEFAULTLIB:library
1>SDL2main.lib(SDL_windows_main.obj) : error LNK2019: unresolved external symbol _SDL_main referenced in function _main
1>C:\Users\Nick\Documents\Visual Studio 2010\Projects\test\Debug\test.exe : fatal error LNK1120: 1 unresolved externals
========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========
You are mixing debug and release builds in the same projrct. Most likely your application is configured for debug, but SDL itself was compiled as release (hence msvcrt.lib warning).
Tjhe fix is to build SDL for debug before you are trying to use it (or any other library that you use).