What actually runs autoconf for the AC_CHECK_FUNCS function

Question

Say in configure.acI am checking for the presence of a C function, e.g.

AC_CHECK_FUNCS( [arc4random] )

And later, the configure process is positive for this function:

checking for arc4random... yes

What actually starts the setup process (say, on a Linux system)? Does it contain an example program and try to compile it?

Answer 1

Creates a test program that declares a function with the same name, then compiles and binds it. Change a few characters in the function name (to make the test fail) and check config.log, you will see the source code of the test program when it fails.