gcc/doc/frontends.texi

@c Copyright (C) 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
@c 1999, 2000, 2001 Free Software Foundation, Inc.
@c This is part of the GCC manual.
@c For copying conditions, see the file gcc.texi.

@node G++ and GCC
@chapter Compile C, C++, Objective-C, Ada, CHILL, Fortran, or Java

@cindex Objective-C
@cindex Fortran
@cindex Java
@cindex CHILL
@cindex Ada
Several versions of the compiler (C, C++, Objective-C, Ada, CHILL,
Fortran, and Java) are integrated; this is why we use the name
``GNU Compiler Collection''.  GCC can compile programs written in any of these
languages.  The Ada, CHILL, Fortran, and Java compilers are described in
separate manuals.

@cindex GCC
``GCC'' is a common shorthand term for the GNU Compiler Collection.  This is both
the most general name for the compiler, and the name used when the
emphasis is on compiling C programs (as the abbreviation formerly
stood for ``GNU C Compiler'').

@cindex C++
@cindex G++
When referring to C++ compilation, it is usual to call the compiler
``G++''.  Since there is only one compiler, it is also accurate to call
it ``GCC'' no matter what the language context; however, the term
``G++'' is more useful when the emphasis is on compiling C++ programs.

@cindex Ada
@cindex GNAT
Similarly, when we talk about Ada compilation, we usually call the
compiler ``GNAT'', for the same reasons.

We use the name ``GCC'' to refer to the compilation system as a
whole, and more specifically to the language-independent part of the
compiler.  For example, we refer to the optimization options as
affecting the behavior of ``GCC'' or sometimes just ``the compiler''.

Front ends for other languages, such as Mercury and Pascal exist but
have not yet been integrated into GCC@.  These front ends, like that for C++,
are built in subdirectories of GCC and link to it.  The result is an
integrated compiler that can compile programs written in C, C++,
Objective-C, or any of the languages for which you have installed front
ends.

In this manual, we only discuss the options for the C, Objective-C, and
C++ compilers and those of the GCC core.  Consult the documentation
of the other front ends for the options to use when compiling programs
written in other languages.

@cindex compiler compared to C++ preprocessor
@cindex intermediate C version, nonexistent
@cindex C intermediate output, nonexistent
G++ is a @emph{compiler}, not merely a preprocessor.  G++ builds object
code directly from your C++ program source.  There is no intermediate C
version of the program.  (By contrast, for example, some other
implementations use a program that generates a C program from your C++
source.)  Avoiding an intermediate C representation of the program means
that you get better object code, and better debugging information.  The
GNU debugger, GDB, works with this information in the object code to
give you comprehensive C++ source-level editing capabilities
(@pxref{C,,C and C++,gdb.info, Debugging with GDB}).

@c FIXME!  Someone who knows something about Objective-C ought to put in
@c a paragraph or two about it here, and move the index entry down when
@c there is more to point to than the general mention in the 1st par.