使用語法：
gcc [ option | filename ]...
g++ [ option | filename ]...
其中 option 為 gcc 使用時的選項(後面會再詳述)，而 filename 為欲以 gcc 處理的文件
說明：
這 C 與 C++ 的 compiler 已將產生新程序的相關程序整合起來。產生一個新的程序需要經過四個階段：預處理、編譯、匯編、連結，而這兩個編譯器都能將輸入的文件做不同階段的處理。雖然原始程序的擴展名可用來分辨編寫原始程序碼所用的語言，但不同的compiler，其預設的處理程序卻各不相同：
gcc 預設經由預處理過(擴展名為.i)的文件為 C 語言，並於程式連結階段以 C 的連結方式處理。
g++ 預設經由預處理過(擴展名為.i)的文件為 C++ 語言，並於程序連結階段以 C++ 的連結方式處理。
原始程序碼的擴展名指出所用編寫程序所用的語言，以及相對應的處理方法：
.c C 原始程序 ； 預處理、編譯、匯編
.C C++ 原始程序 ； 預處理、編譯、匯編
.cc C++ 原始程序 ； 預處理、編譯、匯編
.cxx C++ 原始程序 ； 預處理、編譯、匯編
.m Objective-C 原始程序 ； 預處理、編譯、匯編
.i 已經過預處理之 C 原始程序 ； 編譯、匯編
.ii 已經過預處理之 C++ 原始程序 ； 編譯、匯編
.s 組合語言原始程序 ； 匯編
.S 組合語言原始程序 ； 預處理、匯編
.h 預處理文件(標頭文件) ； (不常出現在指令行)
其他擴展名的文件是由連結程序來處理，通常有：
.o Object file
.a Archive file
除非編譯過程出現錯誤，否則 "連結" 一定是產生一個新程序的最後階段。然而你也可以以 -c、-s 或 -E 等選項，將整個過程自四個階段中的其中一個停止。在連結階段，所有與原始碼相對應的.o 文件、程序庫、和其他無法自文件名辨明屬性的文件(包括不以 .o為擴展名的 object file 以及擴展名為 .a 的 archive file)都會交由連結程序來處理(在指令行將那些文件當作連結程序的參數傳給連結程序)。
選項：
不同的選項必須分開來下：例如 `-dr' 這個選項就與 `-d -r' 大不相同。
絕大部份的 `-f' 及 `-W' 選項都有正反兩種形式：-fname 及-fno-name (或 -Wname 及 -Wno-name)。以下只列出非預設的那個形式。
以下是所有選項的摘要。以形式來分類。選項的意義將另辟小節說明。
一般性(概略、常用的)選項
-c -S -E -o file -pipe -v -x language
程序語言選項
-ansi -fall-virtual -fcond-mismatch
-fdollars-in-identifiers -fenum-int-equiv
-fexternal-templates -fno-asm -fno-builtin
-fno-strict-prototype -fsigned-bitfields
-fsigned-char -fthis-is-variable
-funsigned-bitfields -funsigned-char
-fwritable-strings -traditional -traditional-cpp
-trigraphs
編譯時的警告選項
-fsyntax-only -pedantic -pedantic-errors -w -W
-Wall -Waggregate-return -Wcast-align -Wcast-qual
-Wchar-subscript -Wcomment -Wconversion
-Wenum-clash -Werror -Wformat -Wid-clash-len
-Wimplicit -Winline -Wmissing-prototypes
-Wmissing-declarations -Wnested-externs -Wno-import
-Wparentheses -Wpointer-arith -Wredundant-decls
-Wreturn-type -Wshadow -Wstrict-prototypes -Wswitch
-Wtemplate-debugging -Wtraditional -Wtrigraphs
-Wuninitialized -Wunused -Wwrite-strings
除錯選項
-a -dletters -fpretend-float -g -glevel -gcoff
-gxcoff -gxcoff+ -gdwarf -gdwarf+ -gstabs -gstabs+
-ggdb -p -pg -save-temps -print-file-name=library
-print-libgcc-file-name -print-prog-name=program
最佳化選項
-fcaller-saves -fcse-follow-jumps -fcse-skip-blocks
-fdelayed-branch -felide-constructors
-fexpensive-optimizations -ffast-math -ffloat-store
-fforce-addr -fforce-mem -finline-functions
-fkeep-inline-functions -fmemoize-lookups
-fno-default-inline -fno-defer-pop
-fno-function-cse -fno-inline -fno-peephole
-fomit-frame-pointer -frerun-cse-after-loop
-fschedule-insns -fschedule-insns2
-fstrength-reduce -fthread-jumps -funroll-all-loops
-funroll-loops -O -O2
預處理選項
-Aassertion -C -dD -dM -dN -Dmacro[=defn] -E -H
-idirafter dir -include file -imacros file -iprefix
file -iwithprefix dir -M -MD -MM -MMD -nostdinc -P
-Umacro -undef
匯編程序選項
-Wa,option
連結程序選項
-llibrary -nostartfiles -nostdlib -static -shared
-symbolic -Xlinker option -Wl,option -u symbol
目錄選項
-Bprefix -Idir -I- -Ldir
Target Options
-b machine -V version
與機器(平台)相關的選項
M680x0 Options
-m68000 -m68020 -m68020-40 -m68030 -m68040 -m68881
-mbitfield -mc68000 -mc68020 -mfpa -mnobitfield
-mrtd -mshort -msoft-float
VAX Options
-mg -mgnu -munix
SPARC Options
-mepilogue -mfpu -mhard-float -mno-fpu
-mno-epilogue -msoft-float -msparclite -mv8
-msupersparc -mcypress
Convex Options
-margcount -mc1 -mc2 -mnoargcount
AMD29K Options
-m29000 -m29050 -mbw -mdw -mkernel-registers
-mlarge -mnbw -mnodw -msmall -mstack-check
-muser-registers
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
RS6000 Options
-mfp-in-toc -mno-fop-in-toc
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
-mcpu=cpu type -mips2 -mips3 -mint64 -mlong64
-mlonglong128 -mmips-as -mgas -mrnames -mno-rnames
-mgpopt -mno-gpopt -mstats -mno-stats -mmemcpy
-mno-memcpy -mno-mips-tfile -mmips-tfile
-msoft-float -mhard-float -mabicalls -mno-abicalls
-mhalf-pic -mno-half-pic -G num -nocpp
i386 Options
-m486 -mno-486 -msoft-float -mno-fp-ret-in-387
HPPA Options
-mpa-risc-1-0 -mpa-risc-1-1 -mkernel -mshared-libs
-mno-shared-libs -mlong-calls -mdisable-fpregs
-mdisable-indexing -mtrailing-colon
i960 Options
-mcpu-type -mnumerics -msoft-float
-mleaf-procedures -mno-leaf-procedures -mtail-call
-mno-tail-call -mcomplex-addr -mno-complex-addr
-mcode-align -mno-code-align -mic-compat
-mic2.0-compat -mic3.0-compat -masm-compat
-mintel-asm -mstrict-align -mno-strict-align
-mold-align -mno-old-align
DEC Alpha Options
-mfp-regs -mno-fp-regs -mno-soft-float -msoft-float
System V Options
-G -Qy -Qn -YP,paths -Ym,dir
Code Generation Options
-fcall-saved-reg -fcall-used-reg -ffixed-reg
-finhibit-size-directive -fnonnull-objects
-fno-common -fno-ident -fno-gnu-linker
-fpcc-struct-return -fpic -fPIC
-freg-struct-returno -fshared-data -fshort-enums
-fshort-double -fvolatile -fvolatile-global
-fverbose-asm
PRAGMAS
Two `#pragma' directives are supported for GNU C++, to
permit using the same header file for two purposes: as a
definition of interfaces to a given object class, and as
the full definition of the contents of that object class.
#pragma interface
(C++ only.) Use this directive in header files that define object classes, to save space in most of the object files that use those classes. Nor- mally, local copies of certain information (backup copies of inline member functions, debugging infor-mation, and the internal tables that implement vir-tual functions) must be kept in each object file that includes class definitions. You can use this pragma to avoid such duplication. When a header file containing `#pragma interface' is included in a compilation, this auxiliary information will not be generated (unless the main input source file it-self uses `#pragma implementation'). Instead, the object files will contain references to be resolved at link time.
#pragma implementation
#pragma implementation "objects.h"(C++ only.) Use this pragma in a main input file,when you want full output from included header files to be generated (and made globally visible).
The included header file, in turn, should use`#pragma interface'. Backup copies of inline mem-ber functions, debugging information, and the in-ternal tables used to implement virtual functions are all generated in implementation files.
If you use `#pragma implementation' with no argu-ment, it applies to an include file with the same basename as your source file; for example, in `allclass.cc', `#pragma implementation' by itself is equivalent to `#pragma implementation"allclass.h"'. Use the string argument if you wanta single implementation file to include code frommultiple header files.
There is no way to split up the contents of a sin-gle header file into multiple implementation files.
文件說明
file.c C source file
file.h C header (preprocessor) file
file.i 經預處理過的 C source file
file.C C++ source file
file.cc C++ source file
file.cxx C++ source file
file.m Objective-C source file
file.s assembly language file
file.o object file
a.out link edited output
TMPDIR/cc* temporary files
LIBDIR/cpp preprocessor
LIBDIR/cc1 compiler for C
LIBDIR/cc1plus compiler for C++
LIBDIR/collect linker front end needed on some machines
LIBDIR/libgcc.a GCC subroutine library
/lib/crt[01n].o start-up routine
LIBDIR/ccrt0 additional start-up routine for C++
/lib/libc.a standard C library, 參閱 man page intro(3)
/usr/include standard directory for #include files
LIBDIR/include standard gcc directory for #include files
LIBDIR/g++-include additional g++ directory for #include
LIBDIR is usually /usr/local/lib/machine/version.
TMPDIR comes from the environment variable TMPDIR (default
/usr/tmp if available, else /tmp).
gcc最佳編譯參數 摘要 本文著重介紹在不同的硬件環境下給GCC指定哪些參數才可以得到最佳的性能。
這篇文章是從一個名為Gentoo Linux的發行版的編程說明書裡面分離出來的，希望對大家編譯程序有幫助。
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一、1.2版(gcc 2.9.x版) i386 (Intel), do you really want to install gentoo on that? CHOST="i386-pc-linux-gnu" CFLAGS="-march=i386 -O3 -pipe -fomit-frame-pointer" CXXFLAGS="-march=i386 -O3 -pipe -fomit-frame-pointer"
i486 (Intel), do you really want to install gentoo on that? CHOST="i486-pc-linux-gnu" CFLAGS="-march=i486 -O3 -pipe -fomit-frame-pointer" CXXFLAGS="-march=i486 -O3 -pipe -fomit-frame-pointer"
Pentium, Pentium MMX+, Celeron (Mendocino) (Intel) CHOST="i586-pc-linux-gnu" CFLAGS="-march=pentium -O3 -pipe -fomit-frame-pointer" CXXFLAGS="-march=pentium -O3 -pipe -fomit-frame-pointer"
Pentium Pro/II/III/4, Celeron (Coppermine), Celeron (Willamette?) (Intel) CHOST="i686-pc-linux-gnu" CFLAGS="-march=i686 -O3 -pipe -fomit-frame-pointer" CXXFLAGS="-march=i686 -O3 -pipe -fomit-frame-pointer"
Eden C3/Ezra (Via) CHOST="i586-pc-linux-gnu" CFLAGS="-march=i586 -O3 -pipe -fomit-frame-pointer" CXXFLAGS="-march=i586 -O3 -pipe -fomit-frame-pointer"
Quote : I did the original gentoo install using 1.2, with gcc 2.95 using -march=i586. i686 won't work.
K6 or beyond (AMD) CHOST="i586-pc-linux-gnu" CFLAGS="-march=k6 -O3 -pipe -fomit-frame-pointer" CXXFLAGS="-march=k6 -O3 -pipe -fomit-frame-pointer"
(A Duron will report "Athlon" in its /proc/cpuinfo)
Athlon (AMD) CHOST="i686-pc-linux-gnu" CFLAGS="-march=k6 -O3 -pipe -fomit-frame-pointer" CXXFLAGS="-march=k6 -O3 -pipe -fomit-frame-pointer"
For the following, i don't know of any flag that enhance performances..., do you ?
PowerPC CHOST="powerpc-unknown-linux-gnu" CFLAGS="-O3 -pipe -fomit-frame-pointer" CXXFLAGS="-O3 -pipe -fomit-frame-pointer"
Sparc CHOST="sparc-unknown-linux-gnu" CFLAGS="-O3 -pipe -fomit-frame-pointer" CXXFLAGS="-O3 -pipe -fomit-frame-pointer"
Sparc 64 CHOST="sparc64-unknown-linux-gnu" CFLAGS="-O3 -pipe -fomit-frame-pointer" CXXFLAGS="-O3 -pipe -fomit-frame-pointer"
二、1.4版(gcc 3.x版): i386 (Intel), do you really want to install gentoo on that ? CHOST="i386-pc-linux-gnu" CFLAGS="-march=i386 -O3 -pipe -fomit-frame-pointer" CXXFLAGS="-march=i386 -O3 -pipe -fomit-frame-pointer"
i486 (Intel), do you really want to install gentoo on that ? CHOST="i486-pc-linux-gnu" CFLAGS="-march=i486 -O3 -pipe -fomit-frame-pointer" CXXFLAGS="-march=i486 -O3 -pipe -fomit-frame-pointer"
Pentium 1 (Intel) CHOST="i586-pc-linux-gnu" CFLAGS="-march=pentium -O3 -pipe -fomit-frame-pointer" CXXFLAGS="-march=pentium -O3 -pipe -fomit-frame-pointer"
Pentium MMX (Intel) CHOST="i586-pc-linux-gnu" CFLAGS="-march=pentium-mmx -O3 -pipe -fomit-frame-pointer" CXXFLAGS="-march=pentium-mmx -O3 -pipe -fomit-frame-pointer"
Pentium PRO (Intel) CHOST="i686-pc-linux-gnu" CFLAGS="-march=pentiumpro -O3 -pipe -fomit-frame-pointer" CXXFLAGS="-march=pentiumpro -O3 -pipe -fomit-frame-pointer"
Pentium II (Intel) CHOST="i686-pc-linux-gnu" CFLAGS="-march=pentium2 -O3 -pipe -fomit-frame-pointer" CXXFLAGS="-march=pentium2 -O3 -pipe -fomit-frame-pointer"
Celeron (Mendocino), aka Celeron1 (Intel) CHOST="i686-pc-linux-gnu" CFLAGS="-march=pentium2 -O3 -pipe -fomit-frame-pointer" CXXFLAGS="-march=pentium2 -O3 -pipe -fomit-frame-pointer"
Pentium III (Intel) CHOST="i686-pc-linux-gnu" CFLAGS="-march=pentium3 -O3 -pipe -fomit-frame-pointer" CXXFLAGS="-march=pentium3 -O3 -pipe -fomit-frame-pointer"
Celeron (Coppermine) aka Celeron2 (Intel) CHOST="i686-pc-linux-gnu" CFLAGS="-march=pentium3 -O3 -pipe -fomit-frame-pointer" CXXFLAGS="-march=pentium3 -O3 -pipe -fomit-frame-pointer"
Celeron (Willamette?) (Intel) CHOST="i686-pc-linux-gnu" CFLAGS="-march=pentium4 -O3 -pipe -fomit-frame-pointer" CXXFLAGS="-march=pentium4 -O3 -pipe -fomit-frame-pointer"
Pentium 4 (Intel) CHOST="i686-pc-linux-gnu" CFLAGS="-march=pentium4 -O3 -pipe -fomit-frame-pointer" CXXFLAGS="-march=pentium4 -O3 -pipe -fomit-frame-pointer"
Eden C3/Ezra (Via) CHOST="i586-pc-linux-gnu" CFLAGS="-march=i586 -m3dnow -O3 -pipe -fomit-frame-pointer" CXXFLAGS="-march=i586 -m3dnow -O3 -pipe -fomit-frame-pointer"
quote : the ezra doesn't have any special instructions that you could optimize for, just consider is a K6-3...basically a p2 with 3dnow
K6 (AMD) CHOST="i586-pc-linux-gnu" CFLAGS="-march=k6 -O3 -pipe -fomit-frame-pointer" CXXFLAGS="-march=k6 -O3 -pipe -fomit-frame-pointer"
K6-2 (AMD) CHOST="i586-pc-linux-gnu" CFLAGS="-march=k6-2 -O3 -pipe -fomit-frame-pointer" CXXFLAGS="-march=k6-2 -O3 -pipe -fomit-frame-pointer"
K6-3 (AMD) CHOST="i586-pc-linux-gnu" CFLAGS="-march=k6-3 -O3 -pipe -fomit-frame-pointer" CXXFLAGS="-march=k6-3 -O3 -pipe -fomit-frame-pointer"
Athlon (AMD) CHOST="i686-pc-linux-gnu" CFLAGS="-march=athlon -O3 -pipe -fomit-frame-pointer" CXXFLAGS="-march=athlon -O3 -pipe -fomit-frame-pointer"
Athlon-tbird, aka K7 (AMD) CHOST="i686-pc-linux-gnu" CFLAGS="-march=athlon-tbird -O3 -pipe -fomit-frame-pointer" CXXFLAGS="-march=athlon-tbird -O3 -pipe -fomit-frame-pointer"
Athlon-tbird XP (AMD) CHOST="i686-pc-linux-gnu" CFLAGS="-march=athlon-xp -O3 -pipe -fomit-frame-pointer" CXXFLAGS="-march=athlon-xp -O3 -pipe -fomit-frame-pointer"
Athlon 4(AMD) CHOST="i686-pc-linux-gnu" CFLAGS="-march=athlon-4 -O3 -pipe -fomit-frame-pointer" CXXFLAGS="-march=athlon-4 -O3 -pipe -fomit-frame-pointer"
Athlon XP (AMD) CHOST="i686-pc-linux-gnu" CFLAGS="-march=athlon-xp -O3 -pipe -fomit-frame-pointer" CXXFLAGS="-march=athlon-xp -O3 -pipe -fomit-frame-pointer"
Athlon MP (AMD) CHOST="i686-pc-linux-gnu" CFLAGS="-march=athlon-mp -O3 -pipe -fomit-frame-pointer" CXXFLAGS="-march=athlon-mp -O3 -pipe -fomit-frame-pointer"
603 (PowerPC) CHOST="powerpc-unknown-linux-gnu" CFLAGS="-O3 -pipe -fomit-frame-pointer -fsigned-char" CXXFLAGS="-O3 -pipe -fomit-frame-pointer -fsigned-char"
603e (PowerPC) CHOST="powerpc-unknown-linux-gnu" CFLAGS="-O3 -pipe -fomit-frame-pointer -fsigned-char" CXXFLAGS="-O3 -pipe -fomit-frame-pointer -fsigned-char"
604 (PowerPC) CHOST="powerpc-unknown-linux-gnu" CFLAGS="-O3 -pipe -fomit-frame-pointer -fsigned-char" CXXFLAGS="-O3 -pipe -fomit-frame-pointer -fsigned-char"
604e (PowerPC) CHOST="powerpc-unknown-linux-gnu" CFLAGS="-O3 -pipe -fomit-frame-pointer -fsigned-char" CXXFLAGS="-O3 -pipe -fomit-frame-pointer -fsigned-char"
750 aka as G3 (PowerPC) CHOST="powerpc-unknown-linux-gnu" CFLAGS="-mcpu=750 -O3 -pipe -fomit-frame-pointer -fsigned-char" CXXFLAGS="-mcpu=750 -O3 -pipe -fomit-frame-pointer -fsigned-char"
Note: do not use -march=
7400, aka G4 (PowerPC) CHOST="powerpc-unknown-linux-gnu" CFLAGS="-mcpu=7400 -O3 -pipe -fomit-frame-pointer -fsigned-char -maltivec" CXXFLAGS="-mcpu=7400 -O3 -pipe -fomit-frame-pointer -fsigned-char -maltivec"
Note: do not use -march=
7450, aka G4 second generation (PowerPC) CHOST="powerpc-unknown-linux-gnu" CFLAGS="-mcpu=7450 -O3 -pipe -fomit-frame-pointer -fsigned-char -maltivec" CXXFLAGS="-mcpu=7450 -O3 -pipe -fomit-frame-pointer -fsigned-char -maltivec"
Note: do not use -march=
PowerPC (If you don't know which one) CHOST="powerpc-unknown-linux-gnu" CFLAGS="-O3 -pipe -fomit-frame-pointer -fsigned-char" CXXFLAGS="-O3 -pipe -fomit-frame-pointer -fsigned-char"
Sparc CHOST="sparc-unknown-linux-gnu" CFLAGS="-O3 -pipe -fomit-frame-pointer" CXXFLAGS="-O3 -pipe -fomit-frame-pointer"
Sparc 64 CHOST="sparc64-unknown-linux-gnu" CFLAGS="-O3 -pipe -fomit-frame-pointer" CXXFLAGS="-O3 -pipe -fomit-frame-pointer"GCC 使用指南 GCC 使用指南 GCC 使用指南
