### 3.3 Compiling C++ Programs

C++ source files conventionally use one of the suffixes ``.C` ', ``.cc` ', ``.cpp` ', ``.CPP` ', ``.c++` ', ``.cp` ', or ``.cxx` '; C++ header files often use ``.hh` ' or ``.H` '; and preprocessed C++ files use the suffix ``.ii` '. GCC recognizes files with these names and compiles them as C++ programs even if you call the compiler the same way as for compiling C programs (usually with the name `gcc` ).

However, C++ programs often require class libraries as well as a compiler that understands the C++ language—and under some circumstances, you might want to compile programs or header files from standard input, or otherwise without a suffix that flags them as C++ programs. You might also like to precompile a C header file with a ``.h` ' extension to be used in C++ compilations. `g++` is a program that calls GCC with the default language set to C++, and automatically specifies linking against the C++ library. On many systems, `g++` is also installed with the name `c++` .

When you compile C++ programs, you may specify many of the same command-line options that you use for compiling programs in any language; or command-line options meaningful for C and related languages; or options that are meaningful only for C++ programs. See Options Controlling C Dialect, for explanations of options for languages related to C. See Options Controlling C++ Dialect, for explanations of options that are meaningful only for C++ programs.