The GNU Compiler Collection (GCC) is an integrated collection of compilers for several languages, including C, C++, Java and Fortran.
Our interest here is with the C/C++ compiler .
The g++ command has the following syntax:
| g++ [-option…] file… [option | file]… |
where option denotes an option or switch (see below) and file denotes a file name.
The list of valid options/switches for the g++ command includes the following:
| Option | Purpose |
|---|---|
| c | Compiles without linking |
| Dname=definition | Defines a symbol (as with #define) |
| E | Stop after the preprocessing stage |
| g | Produce debugging information |
| I | Searches the given directory for “includes” |
| llibname | Searches the specified library when linking |
| ofilename | Names the output file |
| M | Instead of preprocessing, output a rule suitable for use by make |
| -help | Provides (some) help |
| -version | Displays the version number |
The following command compiles (but does not link) the C source file named test.c and creates the file test.o:
g++ -c test.c
The following command first defines the symbol DEBUG in the C++ source file named Demo.cpp and then compiles and links it (creating an executable file named Demo).
g++ -DDEBUG=VERBOSE Demo.cpp -o Demo
The following command “includes” files from the directory /myfiles/include in addition to the standard INCLUDE directory.
g++ -I/myfiles/include Demo.cpp -o Demo
The following commands first compile the source files for a small application (written in C) and then links them into an executable named example.
g++ -c account.c g++ -c example.c g++ example.o account.o -o example
Error and warning messages generated by the GCC are often less than clear. There are several places you can go for help, including: