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(gcc-300.info)Invoking GCC

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GCC Command Options
*******************

   When you invoke GCC, it normally does preprocessing, compilation,
assembly and linking.  The "overall options" allow you to stop this
process at an intermediate stage.  For example, the `-c' option says
not to run the linker.  Then the output consists of object files output
by the assembler.

   Other options are passed on to one stage of processing.  Some options
control the preprocessor and others the compiler itself.  Yet other
options control the assembler and linker; most of these are not
documented here, since you rarely need to use any of them.

   Most of the command line options that you can use with GCC are useful
for C programs; when an option is only useful with another language
(usually C++), the explanation says so explicitly.  If the description
for a particular option does not mention a source language, you can use
that option with all supported languages.

   Note: Compiling C++ Programs, for a summary of special
options for compiling C++ programs.

   The `gcc' program accepts options and file names as operands.  Many
options have multi-letter names; therefore multiple single-letter
options may _not_ be grouped: `-dr' is very different from `-d -r'.

   You can mix options and other arguments.  For the most part, the
order you use doesn't matter.  Order does matter when you use several
options of the same kind; for example, if you specify `-L' more than
once, the directories are searched in the order specified.

   Many options have long names starting with `-f' or with `-W'--for
example, `-fforce-mem', `-fstrength-reduce', `-Wformat' and so on.
Most of these have both positive and negative forms; the negative form
of `-ffoo' would be `-fno-foo'.  This manual documents only one of
these two forms, whichever one is not the default.

   Note: Option Index, for an index to GCC's options.

Option Summary

Brief list of all options, without explanations.

Overall Options

Controlling the kind of output:

an executable, object files, assembler files, or preprocessed source.

Invoking G++

Compiling C++ programs.

C Dialect Options

Controlling the variant of C language compiled.

C++ Dialect Options

Variations on C++.

Objective-C Dialect Options

Variations on Objective-C.

Language Independent Options

Controlling how diagnostics should be

formatted.

Warning Options

How picky should the compiler be?

Debugging Options

Symbol tables, measurements, and debugging dumps.

Optimize Options

How much optimization?

Preprocessor Options

Controlling header files and macro definitions.

Also, getting dependency information for Make.

Assembler Options

Passing options to the assembler.

Link Options

Specifying libraries and so on.

Directory Options

Where to find header files and libraries.

Where to find the compiler executable files.

Spec Files

How to pass switches to sub-processes.

Target Options

Running a cross-compiler, or an old version of GCC.

Submodel Options

Specifying minor hardware or convention variations,

such as 68010 vs 68020.

Code Gen Options

Specifying conventions for function calls, data layout

and register usage.

Environment Variables

Env vars that affect GCC.

Running Protoize

Automatically adding or removing function prototypes.