How to find unresolved functions in libraries

Beginning C programmers usually have a problem finding unresolved functions in libraries. Experience tells you e.g. that socket calls are in libsocket.a. But what if you don't know? You can use a combination of standard unix commands to locate those functions. The most useful utilities are "nm" and "grep" together with the powerful "find" command.

at the top of directories with libraries (files with .a extension):
  find . -name "*.a" -exec nm | grep yourUnresolvedFunction) {} \; -print 

Look for the one line where your function name shows up with a "T" symbol in front. This means your functions code is here in this text segment of this library. Of course you can use a full-feaured Integrated Development Environment (IDE) but even then it is good to know how things really work if things go wrong.