How does linker finds standard and WinAPI functions?

Question

When I want to use something from standard C/C++ library I can just include appropriate header and use that function. The same thing with WinAPI functions.

I understand how compiler finds these headers - it searches them localy then if not found looks up in some predefined system folders.

But I cant figure out how does linker findes those libraries because I dont include them in any way...

Answer 1

If you use Visual Studio 2012 with default settings, in addition to C Runtime, linker will link against the following:

kernel32.lib user32.lib gdi32.lib winspool.lib comdlg32.lib advapi32.lib shell32.lib ole32.lib oleaut32.lib uuid.lib odbc32.lib odbccp32.lib

You can see the list yourself if you right click on project, properties -- linker -- input -- additional dependencies.

You can drop some or add some if you want to.

As for the C Runtime, it is controlled by /NODEFAULTLIB linker option, more details here: https://msdn.microsoft.com/en-us/library/3tz4da4a(v=vs.110).aspx

Answer 2

The linker simply has a standard library coming with the compiler itself.
For example, if you install GNU GCC, then you'll see a folder lib which contains all of the static libraries the linker uses to link your code.

If you need to tell the linker to use a specific library or some static libraries from somewhere else, you can always use the -l or -L flags (for GNU GCC) to indicate that you want the linker to use a specific library or folder of libraries.