Using the GNU C Compiler

If you elected to install the development tools package when you installed Ubuntu (or perhaps later on, using synaptic), you should have the GNU C compiler (gcc). Many different options are available for the GNU C compiler, and many of them are similar to those of the C and C++ compilers that are available on other UNIX systems. Look at the man page or information file for gcc for a full list of options and descriptions.

When you build a C program using gcc, the compilation process takes place in several steps:

1.	First, the C preprocessor parses the file. To do so, it sequentially reads the lines, includes header files, and performs macro replacement.
2.	The compiler parses the modified code to determine whether the correct syntax is used. In the process, it builds a symbol table and creates an intermediate object format. Most symbols have specific memory addresses assigned, although symbols defined in other modules, such as external variables, do not.
3.	The last compilation stage, linking, ties together different files and libraries and then links the files by resolving the symbols that had not previously been resolved.

Note

Most C programs compile with a C++ compiler if you follow strict ANSI rules. For example, you can compile the standard hello.c program (everyone's first program) with the GNU C++ compiler. Typically, you name the file something like hello.cc, hello.C, hello.c++, or hello.cxx. The GNU C++ compiler accepts any of these names.