This is doc/gcc.info, produced by makeinfo version 4.5 from doc/gcc.texi. INFO-DIR-SECTION Programming START-INFO-DIR-ENTRY * gcc: (gcc). The GNU Compiler Collection. END-INFO-DIR-ENTRY This file documents the use of the GNU compilers. 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, 2002 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 use the GNU compilers, as well as their features and incompatibilities, and how to report bugs. It corresponds to GCC version 3.2.3. The internals of the GNU compilers, including how to port them to new targets and some information about how to write front ends for new languages, are documented in a separate manual. *Note Introduction: (gccint)Top. * Menu: * G++ and GCC:: You can compile C or C++ programs. * Standards:: Language standards supported by GCC. * Invoking GCC:: Command options supported by `gcc'. * C Implementation:: How GCC implements the ISO C specification. * C Extensions:: GNU extensions to the C language family. * C++ Extensions:: GNU extensions to the C++ language. * Objective-C:: GNU Objective-C runtime features. * Compatibility:: Binary Compatibility * Gcov:: `gcov'---a test coverage program. * Trouble:: If you have trouble using 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. * Funding:: How to help assure funding for free software. * GNU Project:: The GNU Project and GNU/Linux. * 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, Ada, Fortran, or Java ************************************************** Several versions of the compiler (C, C++, Objective-C, Ada, 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, 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. 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. 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-3.1/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".) Errors in the 1999 ISO C standard were corrected in a Technical Corrigendum published in 2001. GCC does not support the uncorrected version. 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 `', `', `', and `'; since AMD1, also those in `'; and in C99, also those in `' and `'. 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, with exceptions noted below. 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. Most of the compiler support routines used by GCC are present in `libgcc', but there are a few exceptions. GCC requires the freestanding environment provide `memcpy', `memmove', `memset' and `memcmp'. Some older ports of GCC are configured to use the BSD `bcopy', `bzero' and `bcmp' functions instead, but this is deprecated for new ports. Finally, if `__builtin_trap' is used, and the target does not implement the `trap' pattern, then GCC will emit a call to `abort'. 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/' is a recent version * `http://www.toodarkpark.org/computers/objc/' is an older example * `http://www.gnustep.org' has additional useful information *Note GNAT Reference Manual: (gnat_rm)Top, for information on standard conformance and compatibility of the Ada compiler. *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: C Implementation, 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 -### --help --target-help --version _C Language Options_ *Note Options Controlling C Dialect: C Dialect Options. -ansi -std=STANDARD -aux-info FILENAME -fno-asm -fno-builtin -fno-builtin-FUNCTION -fhosted -ffreestanding -trigraphs -no-integrated-cpp -traditional -traditional-cpp -fallow-single-precision -fcond-mismatch -fsigned-bitfields -fsigned-char -funsigned-bitfields -funsigned-char -fwritable-strings _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 -fvtable-gc -fno-weak -nostdinc++ -fno-default-inline -Wabi -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 -Wno-deprecated-declarations -Wdisabled-optimization -Wdiv-by-zero -Werror -Wfloat-equal -Wformat -Wformat=2 -Wformat-nonliteral -Wformat-security -Wimplicit -Wimplicit-int -Wimplicit-function-declaration -Werror-implicit-function-declaration -Wimport -Winline -Wlarger-than-LEN -Wlong-long -Wmain -Wmissing-braces -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-declarations -Wmissing-prototypes -Wnested-externs -Wstrict-prototypes -Wtraditional _Debugging Options_ *Note Options for Debugging Your Program or GCC: Debugging Options. -dLETTERS -dumpspecs -dumpmachine -dumpversion -fdump-unnumbered -fdump-translation-unit[-N] -fdump-class-hierarchy[-N] -fdump-tree-original[-N] -fdump-tree-optimized[-N] -fdump-tree-inlined[-N] -fmem-report -fpretend-float -fprofile-arcs -fsched-verbose=N -ftest-coverage -ftime-report -g -gLEVEL -gcoff -gdwarf -gdwarf-1 -gdwarf-1+ -gdwarf-2 -ggdb -gstabs -gstabs+ -gvms -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 -fbounds-check -fbranch-probabilities -fcaller-saves -fcprop-registers -fcse-follow-jumps -fcse-skip-blocks -fdata-sections -fdelayed-branch -fdelete-null-pointer-checks -fexpensive-optimizations -ffast-math -ffloat-store -fforce-addr -fforce-mem -ffunction-sections -fgcse -fgcse-lm -fgcse-sm -finline-functions -finline-limit=N -fkeep-inline-functions -fkeep-static-consts -fmerge-constants -fmerge-all-constants -fmove-all-movables -fno-branch-count-reg -fno-default-inline -fno-defer-pop -fno-function-cse -fno-guess-branch-probability -fno-inline -fno-math-errno -fno-peephole -fno-peephole2 -funsafe-math-optimizations -fno-trapping-math -fomit-frame-pointer -foptimize-register-move -foptimize-sibling-calls -fprefetch-loop-arrays -freduce-all-givs -fregmove -frename-registers -frerun-cse-after-loop -frerun-loop-opt -fschedule-insns -fschedule-insns2 -fno-sched-interblock -fno-sched-spec -fsched-spec-load -fsched-spec-load-dangerous -fsingle-precision-constant -fssa -fssa-ccp -fssa-dce -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 -mfaster-structs -mflat -mfpu -mhard-float -mhard-quad-float -mimpure-text -mlive-g0 -mno-app-regs -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_ -m32rx -m32r -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 -maltivec -mno-altivec -mpowerpc-gpopt -mno-powerpc-gpopt -mpowerpc-gfxopt -mno-powerpc-gfxopt -mnew-mnemonics -mold-mnemonics -mfull-toc -mminimal-toc -mno-fp-in-toc -mno-sum-in-toc -m64 -m32 -mxl-call -mno-xl-call -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 -mcall-netbsd -maix-struct-return -msvr4-struct-return -mabi=altivec -mabi=no-altivec -mprototype -mno-prototype -msim -mmvme -mads -myellowknife -memb -msdata -msdata=OPT -mvxworks -G NUM -pthread _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 -march=CPU-TYPE -mtune=CPU=TYPE -mcpu=CPU-TYPE -membedded-data -muninit-const-in-rodata -membedded-pic -mfp32 -mfp64 -mfused-madd -mno-fused-madd -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 -mflush-func=FUNC -mno-flush-func _i386 and x86-64 Options_ -mcpu=CPU-TYPE -march=CPU-TYPE -mfpmath=UNIT -masm=DIALECT -mno-fancy-math-387 -mno-fp-ret-in-387 -msoft-float -msvr3-shlib -mno-wide-multiply -mrtd -malign-double -mpreferred-stack-boundary=NUM -mmmx -msse -msse2 -m3dnow -mthreads -mno-align-stringops -minline-all-stringops -mpush-args -maccumulate-outgoing-args -m128bit-long-double -m96bit-long-double -mregparm=NUM -momit-leaf-frame-pointer -mno-red-zone -mcmodel=CODE-MODEL -m32 -m64 _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_ -mno-fp-regs -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 -mtune=CPU-TYPE -mbwx -mmax -mfix -mcix -mfloat-vax -mfloat-ieee -mexplicit-relocs -msmall-data -mlarge-data -mmemory-latency=TIME _DEC Alpha/VMS Options_ -mvms-return-codes _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 -m5-64media -m5-64media-nofpu -m5-32media -m5-32media-nofpu -m5-compact -m5-compact-nofpu -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 _MMIX Options_ -mlibfuncs -mno-libfuncs -mepsilon -mno-epsilon -mabi=gnu -mabi=mmixware -mzero-extend -mknuthdiv -mtoplevel-symbols -melf -mbranch-predict -mno-branch-predict -mbase-addresses -mno-base-addresses _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 _D30V Options_ -mextmem -mextmemory -monchip -mno-asm-optimize -masm-optimize -mbranch-cost=N -mcond-exec=N _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 _CRIS Options_ -mcpu=CPU -march=CPU -mtune=CPU -mmax-stack-frame=N -melinux-stacksize=N -metrax4 -metrax100 -mpdebug -mcc-init -mno-side-effects -mstack-align -mdata-align -mconst-align -m32-bit -m16-bit -m8-bit -mno-prologue-epilogue -mno-gotplt -melf -maout -melinux -mlinux -sim -sim2 _PDP-11 Options_ -mfpu -msoft-float -mac0 -mno-ac0 -m40 -m45 -m10 -mbcopy -mbcopy-builtin -mint32 -mno-int16 -mint16 -mno-int32 -mfloat32 -mno-float64 -mfloat64 -mno-float32 -mabshi -mno-abshi -mbranch-expensive -mbranch-cheap -msplit -mno-split -munix-asm -mdec-asm _Xstormy16 Options_ -msim _Xtensa Options_ -mbig-endian -mlittle-endian -mdensity -mno-density -mmac16 -mno-mac16 -mmul16 -mno-mul16 -mmul32 -mno-mul32 -mnsa -mno-nsa -mminmax -mno-minmax -msext -mno-sext -mbooleans -mno-booleans -mhard-float -msoft-float -mfused-madd -mno-fused-madd -mserialize-volatile -mno-serialize-volatile -mtext-section-literals -mno-text-section-literals -mtarget-align -mno-target-align -mlongcalls -mno-longcalls _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 -fasynchronous-unwind-tables -finhibit-size-directive -finstrument-functions -fno-common -fno-ident -fno-gnu-linker -fpcc-struct-return -fpic -fPIC -freg-struct-return -fshared-data -fshort-enums -fshort-double -fshort-wchar -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.ads' Ada source code file which contains a library unit declaration (a declaration of a package, subprogram, or generic, or a generic instantiation), or a library unit renaming declaration (a package, generic, or subprogram renaming declaration). Such files are also called "specs". `FILE.adb' Ada source code file containing a library unit body (a subprogram or package body). Such files are also called "bodies". `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 ada 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. `-###' Like `-v' except the commands are not executed and all command arguments are quoted. This is useful for shell scripts to capture the driver-generated command lines. `-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. `--version' Display the version number and copyrights of the invoked GCC.  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.