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INFO-DIR-SECTION Programming
START-INFO-DIR-ENTRY
* gcc: (gcc).                  The GNU Compiler Collection.
END-INFO-DIR-ENTRY
   This file documents the use and the internals of the GNU compiler.


   Published by the Free Software Foundation
59 Temple Place - Suite 330
Boston, MA 02111-1307 USA


   Copyright (C) 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
1999, 2000, 2001 Free Software Foundation, Inc.


   Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.1 or
any later version published by the Free Software Foundation; with the
Invariant Sections being "GNU General Public License" and "Funding Free
Software", the Front-Cover texts being (a) (see below), and with the
Back-Cover Texts being (b) (see below).  A copy of the license is
included in the section entitled "GNU Free Documentation License".

   (a) The FSF's Front-Cover Text is:

   A GNU Manual

   (b) The FSF's Back-Cover Text is:

   You have freedom to copy and modify this GNU Manual, like GNU
software.  Copies published by the Free Software Foundation raise
funds for GNU development.


File: gcc.info,  Node: Top,  Next: G++ and GCC,  Up: (DIR)

Introduction
************

   This manual documents how to run, install and port the GNU compiler,
as well as its new features and incompatibilities, and how to report
bugs.  It corresponds to GCC version 3.0.

* Menu:


* G++ and GCC::     You can compile C or C++ programs.
* Standards::       Language standards supported by GCC.
* Invoking GCC::    Command options supported by `gcc'.
* Installation::    How to configure, compile and install GCC.
* C Extensions::    GNU extensions to the C language family.
* C++ Extensions::  GNU extensions to the C++ language.
* Objective C::     GNU Objective-C runtime features.
* Gcov::	    gcov: a GCC test coverage program.
* Trouble::         If you have trouble installing GCC.
* Bugs::            How, why and where to report bugs.
* Service::         How to find suppliers of support for GCC.
* Contributing::    How to contribute to testing and developing GCC.
* VMS::             Using GCC on VMS.
* Makefile::        Additional Makefile and configure information.

* Portability::     Goals of GCC's portability features.
* Interface::       Function-call interface of GCC output.
* Passes::          Order of passes, what they do, and what each file is for.
* Trees::           The source representation used by the C and C++ front ends.
* RTL::             The intermediate representation that most passes work on.
* Machine Desc::    How to write machine description instruction patterns.
* Target Macros::   How to write the machine description C macros.
* Config::          Writing the `xm-MACHINE.h' file.
* Fragments::       Writing the `t-TARGET' and `x-HOST' files.

* Funding::         How to help assure funding for free software.
* GNU/Linux::       Linux and the GNU Project

* Copying::         GNU General Public License says
                     how you can copy and share GCC.
* GNU Free Documentation License:: How you can copy and share this manual.
* Contributors::    People who have contributed to GCC.

* Option Index::    Index to command line options.
* Index::	    Index of concepts and symbol names.


File: gcc.info,  Node: G++ and GCC,  Next: Standards,  Prev: Top,  Up: Top

Compile C, C++, Objective C, Fortran, Java
******************************************

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

   "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").

   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.

   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 Ada 95 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.

   G++ is a _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 (*note C
and C++: (gdb.info)C.).


File: gcc.info,  Node: Standards,  Next: Invoking GCC,  Prev: G++ and GCC,  Up: Top

Language Standards Supported by GCC
***********************************

   For each language compiled by GCC for which there is a standard, GCC
attempts to follow one or more versions of that standard, possibly with
some exceptions, and possibly with some extensions.

   GCC supports three versions of the C standard, although support for
the most recent version is not yet complete.

   The original ANSI C standard (X3.159-1989) was ratified in 1989 and
published in 1990.  This standard was ratified as an ISO standard
(ISO/IEC 9899:1990) later in 1990.  There were no technical differences
between these publications, although the sections of the ANSI standard
were renumbered and became clauses in the ISO standard.  This standard,
in both its forms, is commonly known as "C89", or occasionally as
"C90", from the dates of ratification.  The ANSI standard, but not the
ISO standard, also came with a Rationale document.  To select this
standard in GCC, use one of the options `-ansi', `-std=c89' or
`-std=iso9899:1990'; to obtain all the diagnostics required by the
standard, you should also specify `-pedantic' (or `-pedantic-errors' if
you want them to be errors rather than warnings).  *Note Options
Controlling C Dialect: C Dialect Options.

   Errors in the 1990 ISO C standard were corrected in two Technical
Corrigenda published in 1994 and 1996.  GCC does not support the
uncorrected version.

   An amendment to the 1990 standard was published in 1995.  This
amendment added digraphs and `__STDC_VERSION__' to the language, but
otherwise concerned the library.  This amendment is commonly known as
"AMD1"; the amended standard is sometimes known as "C94" or "C95".  To
select this standard in GCC, use the option `-std=iso9899:199409'
(with, as for other standard versions, `-pedantic' to receive all
required diagnostics).

   A new edition of the ISO C standard was published in 1999 as ISO/IEC
9899:1999, and is commonly known as "C99".  GCC has incomplete support
for this standard version; see
`http://gcc.gnu.org/gcc-3.0/c99status.html' for details.  To select this
standard, use `-std=c99' or `-std=iso9899:1999'.  (While in
development, drafts of this standard version were referred to as "C9X".)

   GCC also has some limited support for traditional (pre-ISO) C with
the `-traditional' option.  This support may be of use for compiling
some very old programs that have not been updated to ISO C, but should
not be used for new programs.  It will not work with some modern C
libraries such as the GNU C library.

   By default, GCC provides some extensions to the C language that on
rare occasions conflict with the C standard.  *Note Extensions to the C
Language Family: C Extensions.  Use of the `-std' options listed above
will disable these extensions where they conflict with the C standard
version selected.  You may also select an extended version of the C
language explicitly with `-std=gnu89' (for C89 with GNU extensions) or
`-std=gnu99' (for C99 with GNU extensions).  The default, if no C
language dialect options are given, is `-std=gnu89'; this will change to
`-std=gnu99' in some future release when the C99 support is complete.
Some features that are part of the C99 standard are accepted as
extensions in C89 mode.

   The ISO C standard defines (in clause 4) two classes of conforming
implementation.  A "conforming hosted implementation" supports the
whole standard including all the library facilities; a "conforming
freestanding implementation" is only required to provide certain
library facilities: those in `<float.h>', `<limits.h>', `<stdarg.h>',
and `<stddef.h>'; since AMD1, also those in `<iso646.h>'; and in C99,
also those in `<stdbool.h>' and `<stdint.h>'.  In addition, complex
types, added in C99, are not required for freestanding implementations.
The standard also defines two environments for programs, a
"freestanding environment", required of all implementations and which
may not have library facilities beyond those required of freestanding
implementations, where the handling of program startup and termination
are implementation-defined, and a "hosted environment", which is not
required, in which all the library facilities are provided and startup
is through a function `int main (void)' or `int main (int, char *[])'.
An OS kernel would be a freestanding environment; a program using the
facilities of an operating system would normally be in a hosted
implementation.

   GCC aims towards being usable as a conforming freestanding
implementation, or as the compiler for a conforming hosted
implementation.  By default, it will act as the compiler for a hosted
implementation, defining `__STDC_HOSTED__' as `1' and presuming that
when the names of ISO C functions are used, they have the semantics
defined in the standard.  To make it act as a conforming freestanding
implementation for a freestanding environment, use the option
`-ffreestanding'; it will then define `__STDC_HOSTED__' to `0' and not
make assumptions about the meanings of function names from the standard
library.  To build an OS kernel, you may well still need to make your
own arrangements for linking and startup.  *Note Options Controlling C
Dialect: C Dialect Options.

   GCC does not provide the library facilities required only of hosted
implementations, nor yet all the facilities required by C99 of
freestanding implementations; to use the facilities of a hosted
environment, you will need to find them elsewhere (for example, in the
GNU C library).  *Note Standard Libraries: Standard Libraries.

   For references to Technical Corrigenda, Rationale documents and
information concerning the history of C that is available online, see
`http://gcc.gnu.org/readings.html'

   There is no formal written standard for Objective-C.  The most
authoritative manual is "Object-Oriented Programming and the
Objective-C Language", available at a number of web sites;
`http://developer.apple.com/techpubs/macosx/Cocoa/ObjectiveC/' has a
recent version, while `http://www.toodarkpark.org/computers/objc/' is
an older example.  `http://www.gnustep.org' includes useful information
as well.

   *Note The GNU Fortran Language: (g77)Language, for details of the
Fortran language supported by GCC.

   *Note Compatibility with the Java Platform: (gcj)Compatibility, for
details of compatibility between `gcj' and the Java Platform.


File: gcc.info,  Node: Invoking GCC,  Next: Installation,  Prev: Standards,  Up: Top

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: Invoking G++, 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.

* Menu:

* 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.


File: gcc.info,  Node: Option Summary,  Next: Overall Options,  Up: Invoking GCC

Option Summary
==============

   Here is a summary of all the options, grouped by type.  Explanations
are in the following sections.

_Overall Options_
     *Note Options Controlling the Kind of Output: Overall Options.
          -c  -S  -E  -o FILE  -pipe  -pass-exit-codes  -x LANGUAGE 
          -v  --target-help  --help

_C Language Options_
     *Note Options Controlling C Dialect: C Dialect Options.
          -ansi  -std=STANDARD  -aux-info FILENAME 
          -fno-asm  -fno-builtin 
          -fhosted  -ffreestanding 
          -trigraphs  -traditional  -traditional-cpp 
          -fallow-single-precision  -fcond-mismatch 
          -fsigned-bitfields  -fsigned-char 
          -funsigned-bitfields  -funsigned-char 
          -fwritable-strings  -fshort-wchar

_C++ Language Options_
     *Note Options Controlling C++ Dialect: C++ Dialect Options.
          -fno-access-control  -fcheck-new  -fconserve-space 
          -fno-const-strings  -fdollars-in-identifiers 
          -fno-elide-constructors 
          -fno-enforce-eh-specs  -fexternal-templates 
          -falt-external-templates 
          -ffor-scope  -fno-for-scope  -fno-gnu-keywords 
          -fno-implicit-templates 
          -fno-implicit-inline-templates 
          -fno-implement-inlines  -fms-extensions 
          -fno-nonansi-builtins  -fno-operator-names 
          -fno-optional-diags  -fpermissive 
          -frepo  -fno-rtti  -fstats  -ftemplate-depth-N 
          -fuse-cxa-atexit  -fno-weak  -nostdinc++ 
          -fno-default-inline  -Wctor-dtor-privacy 
          -Wnon-virtual-dtor  -Wreorder 
          -Weffc++  -Wno-deprecated 
          -Wno-non-template-friend  -Wold-style-cast 
          -Woverloaded-virtual  -Wno-pmf-conversions 
          -Wsign-promo  -Wsynth

_Objective-C Language Options_
     *Note Options Controlling Objective-C Dialect: Objective-C Dialect
     Options.
          -fconstant-string-class=CLASS-NAME 
          -fgnu-runtime  -fnext-runtime  -gen-decls 
          -Wno-protocol  -Wselector

_Language Independent Options_
     *Note Options to Control Diagnostic Messages Formatting: Language
     Independent Options.
          -fmessage-length=N  
          -fdiagnostics-show-location=[once|every-line]

_Warning Options_
     *Note Options to Request or Suppress Warnings: Warning Options.
          -fsyntax-only  -pedantic  -pedantic-errors 
          -w  -W  -Wall  -Waggregate-return 
          -Wcast-align  -Wcast-qual  -Wchar-subscripts  -Wcomment 
          -Wconversion  -Wdisabled-optimization -Werror 
          -Wfloat-equal  -Wformat  -Wformat=2 
          -Wformat-nonliteral  -Wformat-security 
          -Wid-clash-LEN  -Wimplicit -Wimplicit-int 
          -Wimplicit-function-declaration 
          -Werror-implicit-function-declaration 
          -Wimport  -Winline 
          -Wlarger-than-LEN  -Wlong-long 
          -Wmain  -Wmissing-braces  -Wmissing-declarations 
          -Wmissing-format-attribute  -Wmissing-noreturn 
          -Wmultichar  -Wno-format-extra-args -Wno-format-y2k 
          -Wno-import  -Wpacked  -Wpadded 
          -Wparentheses  -Wpointer-arith  -Wredundant-decls 
          -Wreturn-type  -Wsequence-point  -Wshadow 
          -Wsign-compare  -Wswitch  -Wsystem-headers 
          -Wtrigraphs  -Wundef  -Wuninitialized 
          -Wunknown-pragmas  -Wunreachable-code 
          -Wunused  -Wunused-function  -Wunused-label  -Wunused-parameter 
          -Wunused-value  -Wunused-variable  -Wwrite-strings

_C-only Warning Options_
          -Wbad-function-cast  -Wmissing-prototypes  -Wnested-externs 
          -Wstrict-prototypes  -Wtraditional

_Debugging Options_
     *Note Options for Debugging Your Program or GCC: Debugging Options.
          -a  -ax  -dLETTERS  -dumpspecs  -dumpmachine  -dumpversion 
          -fdump-unnumbered -fdump-translation-unit[-N] 
          -fdump-class-hierarchy[-N] 
          -fdump-ast-original[-N] -fdump-ast-optimized[-N] 
          -fmem-report  -fpretend-float 
          -fprofile-arcs  -ftest-coverage  -ftime-report 
          -g  -gLEVEL  -gcoff  -gdwarf  -gdwarf-1  -gdwarf-1+  -gdwarf-2 
          -ggdb  -gstabs  -gstabs+  -gxcoff  -gxcoff+ 
          -p  -pg  -print-file-name=LIBRARY  -print-libgcc-file-name 
          -print-multi-directory  -print-multi-lib 
          -print-prog-name=PROGRAM  -print-search-dirs  -Q 
          -save-temps  -time

_Optimization Options_
     *Note Options that Control Optimization: Optimize Options.
          -falign-functions=N  -falign-jumps=N 
          -falign-labels=N  -falign-loops=N  
          -fbranch-probabilities  -fcaller-saves 
          -fcse-follow-jumps  -fcse-skip-blocks  -fdata-sections  -fdce 
          -fdelayed-branch  -fdelete-null-pointer-checks 
          -fexpensive-optimizations  -ffast-math  -ffloat-store 
          -fforce-addr  -fforce-mem  -ffunction-sections  -fgcse  
          -finline-functions  -finline-limit=N  -fkeep-inline-functions 
          -fkeep-static-consts  -fmove-all-movables 
          -fno-default-inline  -fno-defer-pop 
          -fno-function-cse  -fno-guess-branch-probability 
          -fno-inline  -fno-math-errno  -fno-peephole  -fno-peephole2 
          -fomit-frame-pointer  -foptimize-register-move 
          -foptimize-sibling-calls  -freduce-all-givs 
          -fregmove  -frename-registers 
          -frerun-cse-after-loop  -frerun-loop-opt 
          -fschedule-insns  -fschedule-insns2 
          -fsingle-precision-constant  -fssa 
          -fstrength-reduce  -fstrict-aliasing  -fthread-jumps  -ftrapv 
          -funroll-all-loops  -funroll-loops  
          --param NAME=VALUE
          -O  -O0  -O1  -O2  -O3  -Os

_Preprocessor Options_
     *Note Options Controlling the Preprocessor: Preprocessor Options.
          -$  -AQUESTION=ANSWER  -A-QUESTION[=ANSWER] 
          -C  -dD  -dI  -dM  -dN 
          -DMACRO[=DEFN]  -E  -H 
          -idirafter DIR 
          -include FILE  -imacros FILE 
          -iprefix FILE  -iwithprefix DIR 
          -iwithprefixbefore DIR  -isystem DIR 
          -M  -MM  -MF  -MG  -MP  -MQ  -MT  -nostdinc  -P  -remap 
          -trigraphs  -undef  -UMACRO  -Wp,OPTION

_Assembler Option_
     *Note Passing Options to the Assembler: Assembler Options.
          -Wa,OPTION

_Linker Options_
     *Note Options for Linking: Link Options.
          OBJECT-FILE-NAME  -lLIBRARY 
          -nostartfiles  -nodefaultlibs  -nostdlib 
          -s  -static  -static-libgcc  -shared  -shared-libgcc  -symbolic 
          -Wl,OPTION  -Xlinker OPTION 
          -u SYMBOL

_Directory Options_
     *Note Options for Directory Search: Directory Options.
          -BPREFIX  -IDIR  -I-  -LDIR  -specs=FILE

_Target Options_
     *Note Target Options::.
          -b MACHINE  -V VERSION

_Machine Dependent Options_
     *Note Hardware Models and Configurations: Submodel Options.
     _M680x0 Options_
          -m68000  -m68020  -m68020-40  -m68020-60  -m68030  -m68040 
          -m68060  -mcpu32 -m5200  -m68881  -mbitfield  -mc68000  -mc68020   
          -mfpa  -mnobitfield  -mrtd  -mshort  -msoft-float  -mpcrel 
          -malign-int  -mstrict-align

     _M68hc1x Options_
          -m6811  -m6812  -m68hc11  -m68hc12 
          -mauto-incdec  -mshort  -msoft-reg-count=COUNT

     _VAX Options_
          -mg  -mgnu  -munix

     _SPARC Options_
          -mcpu=CPU-TYPE 
          -mtune=CPU-TYPE 
          -mcmodel=CODE-MODEL 
          -m32  -m64 
          -mapp-regs  -mbroken-saverestore  -mcypress 
          -mepilogue  -mfaster-structs -mflat 
          -mfpu  -mhard-float  -mhard-quad-float 
          -mimpure-text  -mlive-g0  -mno-app-regs 
          -mno-epilogue  -mno-faster-structs  -mno-flat  -mno-fpu 
          -mno-impure-text  -mno-stack-bias  -mno-unaligned-doubles 
          -msoft-float  -msoft-quad-float  -msparclite  -mstack-bias 
          -msupersparc  -munaligned-doubles  -mv8

     _Convex Options_
          -mc1  -mc2  -mc32  -mc34  -mc38 
          -margcount  -mnoargcount 
          -mlong32  -mlong64 
          -mvolatile-cache  -mvolatile-nocache

     _AMD29K Options_
          -m29000  -m29050  -mbw  -mnbw  -mdw  -mndw 
          -mlarge  -mnormal  -msmall 
          -mkernel-registers  -mno-reuse-arg-regs 
          -mno-stack-check  -mno-storem-bug 
          -mreuse-arg-regs  -msoft-float  -mstack-check 
          -mstorem-bug  -muser-registers

     _ARM Options_
          -mapcs-frame  -mno-apcs-frame 
          -mapcs-26  -mapcs-32 
          -mapcs-stack-check  -mno-apcs-stack-check 
          -mapcs-float  -mno-apcs-float 
          -mapcs-reentrant  -mno-apcs-reentrant 
          -msched-prolog  -mno-sched-prolog 
          -mlittle-endian  -mbig-endian  -mwords-little-endian 
          -malignment-traps  -mno-alignment-traps 
          -msoft-float  -mhard-float  -mfpe 
          -mthumb-interwork  -mno-thumb-interwork 
          -mcpu=NAME  -march=NAME  -mfpe=NAME  
          -mstructure-size-boundary=N 
          -mbsd -mxopen  -mno-symrename 
          -mabort-on-noreturn 
          -mlong-calls  -mno-long-calls 
          -msingle-pic-base  -mno-single-pic-base 
          -mpic-register=REG 
          -mnop-fun-dllimport 
          -mpoke-function-name 
          -mthumb  -marm 
          -mtpcs-frame  -mtpcs-leaf-frame 
          -mcaller-super-interworking  -mcallee-super-interworking

     _MN10200 Options_
          -mrelax

     _MN10300 Options_
          -mmult-bug  -mno-mult-bug 
          -mam33  -mno-am33 
          -mno-crt0  -mrelax

     _M32R/D Options_
          -mcode-model=MODEL-TYPE  -msdata=SDATA-TYPE 
          -G NUM

     _M88K Options_
          -m88000  -m88100  -m88110  -mbig-pic 
          -mcheck-zero-division  -mhandle-large-shift 
          -midentify-revision  -mno-check-zero-division 
          -mno-ocs-debug-info  -mno-ocs-frame-position 
          -mno-optimize-arg-area  -mno-serialize-volatile 
          -mno-underscores  -mocs-debug-info 
          -mocs-frame-position  -moptimize-arg-area 
          -mserialize-volatile  -mshort-data-NUM  -msvr3 
          -msvr4  -mtrap-large-shift  -muse-div-instruction 
          -mversion-03.00  -mwarn-passed-structs

     _RS/6000 and PowerPC Options_
          -mcpu=CPU-TYPE 
          -mtune=CPU-TYPE 
          -mpower  -mno-power  -mpower2  -mno-power2 
          -mpowerpc  -mpowerpc64  -mno-powerpc 
          -mpowerpc-gpopt  -mno-powerpc-gpopt 
          -mpowerpc-gfxopt  -mno-powerpc-gfxopt 
          -mnew-mnemonics  -mold-mnemonics 
          -mfull-toc   -mminimal-toc  -mno-fop-in-toc  -mno-sum-in-toc 
          -m64  -m32  -mxl-call  -mno-xl-call  -mthreads  -mpe 
          -msoft-float  -mhard-float  -mmultiple  -mno-multiple 
          -mstring  -mno-string  -mupdate  -mno-update 
          -mfused-madd  -mno-fused-madd  -mbit-align  -mno-bit-align 
          -mstrict-align  -mno-strict-align  -mrelocatable 
          -mno-relocatable  -mrelocatable-lib  -mno-relocatable-lib 
          -mtoc  -mno-toc -mlittle  -mlittle-endian  -mbig  -mbig-endian 
          -mcall-aix  -mcall-sysv  -mprototype  -mno-prototype 
          -msim  -mmvme  -mads  -myellowknife  -memb -msdata 
          -msdata=OPT  -mvxworks -G NUM

     _RT Options_
          -mcall-lib-mul  -mfp-arg-in-fpregs  -mfp-arg-in-gregs 
          -mfull-fp-blocks  -mhc-struct-return  -min-line-mul 
          -mminimum-fp-blocks  -mnohc-struct-return

     _MIPS Options_
          -mabicalls  -mcpu=CPU-TYPE 
          -membedded-data  -muninit-const-in-rodata 
          -membedded-pic  -mfp32  -mfp64  -mgas  -mgp32  -mgp64 
          -mgpopt  -mhalf-pic  -mhard-float  -mint64  -mips1 
          -mips2  -mips3  -mips4  -mlong64  -mlong32  -mlong-calls  -mmemcpy 
          -mmips-as  -mmips-tfile  -mno-abicalls 
          -mno-embedded-data  -mno-uninit-const-in-rodata 
          -mno-embedded-pic  -mno-gpopt  -mno-long-calls 
          -mno-memcpy  -mno-mips-tfile  -mno-rnames  -mno-stats 
          -mrnames  -msoft-float 
          -m4650  -msingle-float  -mmad 
          -mstats  -EL  -EB  -G NUM  -nocpp 
          -mabi=32  -mabi=n32  -mabi=64  -mabi=eabi 
          -mfix7000  -mno-crt0

     _i386 Options_
          -mcpu=CPU-TYPE  -march=CPU-TYPE 
          -mintel-syntax -mieee-fp  -mno-fancy-math-387 
          -mno-fp-ret-in-387  -msoft-float  -msvr3-shlib 
          -mno-wide-multiply  -mrtd  -malign-double 
          -mreg-alloc=LIST  -mregparm=NUM 
          -malign-jumps=NUM  -malign-loops=NUM 
          -malign-functions=NUM  -mpreferred-stack-boundary=NUM 
          -mthreads  -mno-align-stringops  -minline-all-stringops 
          -mpush-args  -maccumulate-outgoing-args  -m128bit-long-double 
          -m96bit-long-double  -momit-leaf-frame-pointer

     _HPPA Options_
          -march=ARCHITECTURE-TYPE 
          -mbig-switch  -mdisable-fpregs  -mdisable-indexing 
          -mfast-indirect-calls -mgas  -mjump-in-delay 
          -mlong-load-store  -mno-big-switch  -mno-disable-fpregs 
          -mno-disable-indexing  -mno-fast-indirect-calls  -mno-gas 
          -mno-jump-in-delay  -mno-long-load-store 
          -mno-portable-runtime  -mno-soft-float 
          -mno-space-regs  -msoft-float  -mpa-risc-1-0 
          -mpa-risc-1-1  -mpa-risc-2-0 -mportable-runtime 
          -mschedule=CPU-TYPE  -mspace-regs

     _Intel 960 Options_
          -mCPU-TYPE  -masm-compat  -mclean-linkage 
          -mcode-align  -mcomplex-addr  -mleaf-procedures 
          -mic-compat  -mic2.0-compat  -mic3.0-compat 
          -mintel-asm  -mno-clean-linkage  -mno-code-align 
          -mno-complex-addr  -mno-leaf-procedures 
          -mno-old-align  -mno-strict-align  -mno-tail-call 
          -mnumerics  -mold-align  -msoft-float  -mstrict-align 
          -mtail-call

     _DEC Alpha Options_
          -mfp-regs  -mno-fp-regs  -mno-soft-float  -msoft-float 
          -malpha-as  -mgas 
          -mieee  -mieee-with-inexact  -mieee-conformant 
          -mfp-trap-mode=MODE  -mfp-rounding-mode=MODE 
          -mtrap-precision=MODE  -mbuild-constants 
          -mcpu=CPU-TYPE 
          -mbwx  -mno-bwx  -mcix  -mno-cix  -mmax  -mno-max 
          -mmemory-latency=TIME

     _Clipper Options_
          -mc300  -mc400

     _H8/300 Options_
          -mrelax  -mh  -ms  -mint32  -malign-300

     _SH Options_
          -m1  -m2  -m3  -m3e 
          -m4-nofpu  -m4-single-only  -m4-single  -m4 
          -mb  -ml  -mdalign  -mrelax 
          -mbigtable  -mfmovd  -mhitachi  -mnomacsave 
          -mieee  -misize  -mpadstruct  -mspace 
          -mprefergot  -musermode

     _System V Options_
          -Qy  -Qn  -YP,PATHS  -Ym,DIR

     _ARC Options_
          -EB  -EL 
          -mmangle-cpu  -mcpu=CPU  -mtext=TEXT-SECTION 
          -mdata=DATA-SECTION  -mrodata=READONLY-DATA-SECTION

     _TMS320C3x/C4x Options_
          -mcpu=CPU  -mbig  -msmall  -mregparm  -mmemparm 
          -mfast-fix  -mmpyi  -mbk  -mti  -mdp-isr-reload 
          -mrpts=COUNT  -mrptb  -mdb  -mloop-unsigned 
          -mparallel-insns  -mparallel-mpy  -mpreserve-float

     _V850 Options_
          -mlong-calls  -mno-long-calls  -mep  -mno-ep 
          -mprolog-function  -mno-prolog-function  -mspace 
          -mtda=N  -msda=N  -mzda=N 
          -mv850  -mbig-switch

     _NS32K Options_
          -m32032  -m32332  -m32532  -m32081  -m32381 
          -mmult-add  -mnomult-add -msoft-float  -mrtd  -mnortd 
          -mregparam  -mnoregparam  -msb  -mnosb 
          -mbitfield  -mnobitfield  -mhimem  -mnohimem

     _AVR Options_
          -mmcu=MCU  -msize  -minit-stack=N  -mno-interrupts 
          -mcall-prologues  -mno-tablejump  -mtiny-stack

     _MCore Options_
          -mhardlit  -mno-hardlit  -mdiv  -mno-div  -mrelax-immediates  
          -mno-relax-immediates  -mwide-bitfields  -mno-wide-bitfields 
          -m4byte-functions  -mno-4byte-functions  -mcallgraph-data 
          -mno-callgraph-data  -mslow-bytes  -mno-slow-bytes  -mno-lsim 
          -mlittle-endian  -mbig-endian  -m210  -m340  -mstack-increment

     _IA-64 Options_
          -mbig-endian  -mlittle-endian  -mgnu-as  -mgnu-ld  -mno-pic 
          -mvolatile-asm-stop  -mb-step  -mregister-names  -mno-sdata 
          -mconstant-gp  -mauto-pic  -minline-divide-min-latency 
          -minline-divide-max-throughput  -mno-dwarf2-asm 
          -mfixed-range=REGISTER-RANGE

     _S/390 and zSeries Options_
          -mhard-float  -msoft-float  -mbackchain  -mno-backchain 
          -msmall-exec  -mno-small-exec  -mmvcle -mno-mvcle 
          -m64 -m31 -mdebug -mno-debug

_Code Generation Options_
     *Note Options for Code Generation Conventions: Code Gen Options.
          -fcall-saved-REG  -fcall-used-REG 
          -ffixed-REG -fexceptions 
          -fnon-call-exceptions  -funwind-tables 
          -finhibit-size-directive  -finstrument-functions 
          -fcheck-memory-usage  -fprefix-function-name 
          -fno-common  -fno-ident  -fno-gnu-linker 
          -fpcc-struct-return  -fpic  -fPIC 
          -freg-struct-return  -fshared-data  -fshort-enums 
          -fshort-double  -fvolatile 
          -fvolatile-global  -fvolatile-static 
          -fverbose-asm  -fpack-struct  -fstack-check 
          -fstack-limit-register=REG  -fstack-limit-symbol=SYM 
          -fargument-alias  -fargument-noalias 
          -fargument-noalias-global  -fleading-underscore

* Menu:

* Overall Options::     Controlling the kind of output:
                        an executable, object files, assembler files,
                        or preprocessed source.
* 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.


File: gcc.info,  Node: Overall Options,  Next: Invoking G++,  Prev: Option Summary,  Up: Invoking GCC

Options Controlling the Kind of Output
======================================

   Compilation can involve up to four stages: preprocessing, compilation
proper, assembly and linking, always in that order.  The first three
stages apply to an individual source file, and end by producing an
object file; linking combines all the object files (those newly
compiled, and those specified as input) into an executable file.

   For any given input file, the file name suffix determines what kind
of compilation is done:

`FILE.c'
     C source code which must be preprocessed.

`FILE.i'
     C source code which should not be preprocessed.

`FILE.ii'
     C++ source code which should not be preprocessed.

`FILE.m'
     Objective-C source code.  Note that you must link with the library
     `libobjc.a' to make an Objective-C program work.

`FILE.mi'
     Objective-C source code which should not be preprocessed.

`FILE.h'
     C header file (not to be compiled or linked).

`FILE.cc'
`FILE.cp'
`FILE.cxx'
`FILE.cpp'
`FILE.c++'
`FILE.C'
     C++ source code which must be preprocessed.  Note that in `.cxx',
     the last two letters must both be literally `x'.  Likewise, `.C'
     refers to a literal capital C.

`FILE.f'
`FILE.for'
`FILE.FOR'
     Fortran source code which should not be preprocessed.

`FILE.F'
`FILE.fpp'
`FILE.FPP'
     Fortran source code which must be preprocessed (with the
     traditional preprocessor).

`FILE.r'
     Fortran source code which must be preprocessed with a RATFOR
     preprocessor (not included with GCC).

     *Note Options Controlling the Kind of Output: (g77)Overall
     Options, for more details of the handling of Fortran input files.

`FILE.s'
     Assembler code.

`FILE.S'
     Assembler code which must be preprocessed.

`OTHER'
     An object file to be fed straight into linking.  Any file name
     with no recognized suffix is treated this way.

   You can specify the input language explicitly with the `-x' option:

`-x LANGUAGE'
     Specify explicitly the LANGUAGE for the following input files
     (rather than letting the compiler choose a default based on the
     file name suffix).  This option applies to all following input
     files until the next `-x' option.  Possible values for LANGUAGE
     are:
          c  c-header  cpp-output
          c++  c++-cpp-output
          objective-c  objc-cpp-output
          assembler  assembler-with-cpp
          f77  f77-cpp-input  ratfor
          java

`-x none'
     Turn off any specification of a language, so that subsequent files
     are handled according to their file name suffixes (as they are if
     `-x' has not been used at all).

`-pass-exit-codes'
     Normally the `gcc' program will exit with the code of 1 if any
     phase of the compiler returns a non-success return code.  If you
     specify `-pass-exit-codes', the `gcc' program will instead return
     with numerically highest error produced by any phase that returned
     an error indication.

   If you only want some of the stages of compilation, you can use `-x'
(or filename suffixes) to tell `gcc' where to start, and one of the
options `-c', `-S', or `-E' to say where `gcc' is to stop.  Note that
some combinations (for example, `-x cpp-output -E') instruct `gcc' to
do nothing at all.

`-c'
     Compile or assemble the source files, but do not link.  The linking
     stage simply is not done.  The ultimate output is in the form of an
     object file for each source file.

     By default, the object file name for a source file is made by
     replacing the suffix `.c', `.i', `.s', etc., with `.o'.

     Unrecognized input files, not requiring compilation or assembly,
     are ignored.

`-S'
     Stop after the stage of compilation proper; do not assemble.  The
     output is in the form of an assembler code file for each
     non-assembler input file specified.

     By default, the assembler file name for a source file is made by
     replacing the suffix `.c', `.i', etc., with `.s'.

     Input files that don't require compilation are ignored.

`-E'
     Stop after the preprocessing stage; do not run the compiler
     proper.  The output is in the form of preprocessed source code,
     which is sent to the standard output.

     Input files which don't require preprocessing are ignored.

`-o FILE'
     Place output in file FILE.  This applies regardless to whatever
     sort of output is being produced, whether it be an executable file,
     an object file, an assembler file or preprocessed C code.

     Since only one output file can be specified, it does not make
     sense to use `-o' when compiling more than one input file, unless
     you are producing an executable file as output.

     If `-o' is not specified, the default is to put an executable file
     in `a.out', the object file for `SOURCE.SUFFIX' in `SOURCE.o', its
     assembler file in `SOURCE.s', and all preprocessed C source on
     standard output.

`-v'
     Print (on standard error output) the commands executed to run the
     stages of compilation.  Also print the version number of the
     compiler driver program and of the preprocessor and the compiler
     proper.

`-pipe'
     Use pipes rather than temporary files for communication between the
     various stages of compilation.  This fails to work on some systems
     where the assembler is unable to read from a pipe; but the GNU
     assembler has no trouble.

`--help'
     Print (on the standard output) a description of the command line
     options understood by `gcc'.  If the `-v' option is also specified
     then `--help' will also be passed on to the various processes
     invoked by `gcc', so that they can display the command line options
     they accept.  If the `-W' option is also specified then command
     line options which have no documentation associated with them will
     also be displayed.

`--target-help'
     Print (on the standard output) a description of target specific
     command line options for each tool.


File: gcc.info,  Node: Invoking G++,  Next: C Dialect Options,  Prev: Overall Options,  Up: Invoking GCC

Compiling C++ Programs
======================

   C++ source files conventionally use one of the suffixes `.C', `.cc',
`.cpp', `.c++', `.cp', or `.cxx'; 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 from standard input,
or otherwise without a suffix that flags them as C++ programs.  `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.  *Note
Options Controlling C Dialect: C Dialect Options, for explanations of
options for languages related to C.  *Note Options Controlling C++
Dialect: C++ Dialect Options, for explanations of options that are
meaningful only for C++ programs.

