[judofyr]

This is called computed (or assigned) goto and is a GCC extension (that is, not in the C standard): http://gcc.gnu.org/onlinedocs/gcc/Labels-as-Values.html

[binarycrusader]

Note that other compilers (such as Oracle Solaris Studio) support computed gotos as well:

  http://docs.oracle.com/cd/E19205-01/820-7598/bjabt/index.html

And LLVM:

  http://blog.llvm.org/2010/01/address-of-label-and-indirect-branches.html