C - Undefined symbols for architecture x86_64 when compiling on Mac OSX Lion

Question

I\'m getting some problems on compiling a very very simple name.c file on Mac OSX Lion.

Now, I started following Harvard CS50 course on cs50.net. I\'m not totally ne

Answer 1

The problem you encounter is in the linking stage, not compiling. You did not provide the implementation of GetString, only its declaration (through the .h file you #include).

To provide the implementation itself, you usually need to link against the library which includes it; this is usually done by the -l flag to g++. For example,

g++ file.cpp -lcs50

Your second sample code does link, because you manually (and explicitly) provide an implementation for GetString, though an empty one.