使用语法：
gcc [ option | filename ]...
g [ option | filename ]...
其中 option 为 gcc 使用时的选项(后面会再详述)，
而 filename 为欲以 gcc 处理的文件
说明：
这 C 与 C 的 compiler 已将产生新程序的相关程序整合起来。产
生一个新的程序需要经过四个阶段：预处理、编译、汇编,连结，
而这两个编译器都能将输入的文件做不同阶段的处理。虽然原始程序
的扩展名可用来分辨编写原始程序码所用的语言，但不同的 compiler
，其预设的处理程序却各不相同：
gcc 预设经由预处理过(扩展名为.i)的文件为 C 语言，并於程
式连结阶段以 C 的连结方式处理。
g 预设经由预处理过(扩展名为.i)的文件为 C 语言，并於程
序连结阶段以 C 的连结方式处理。
原始程序码的扩展名指出所用编写程序所用的语言，以及相对应的处
理方法：
.c C 原始程序 ； 预处理、编译、汇编
.C C 原始程序 ； 预处理、编译、汇编
.cc C 原始程序 ； 预处理、编译、汇编
.cxx C 原始程序 ； 预处理、编译、汇编
.m Objective-C 原始程序 ； 预处理、编译、汇编
.i 已经过预处理之 C 原始程序 ； 编译、汇编
.ii 已经过预处理之 C 原始程序 ； 编译、汇编
.s 组合语言原始程序 ； 汇编
.S 组合语言原始程序 ； 预处理、汇编
.h 预处理文件(标头文件) ； (不常出现在指令行)
其他扩展名的文件是由连结程序来处理，通常有：
.o Object file
.a Archive file
除非编译过程出现错误，否则 "连结" 一定是产生一个新程序的最
後阶段。然而你也可以以 -c、-s 或 -E 等选项，将整个过程自四
个阶段中的其中一个停止。在连结阶段，所有与原始码相对应的
.o 文件、程序库、和其他无法自文件名辨明属性的文件(包括不以 .o
为扩展名的 object file 以及扩展名为 .a 的 archive file)都会
交由连结程序来处理(在指令行将那些文件当作连结程序的参数传给
连结程序)。
选项：
不同的选项必须分开来下：例如 `-dr' 这个选项就与 `-d -r' 大
不相同。
绝大部份的 `-f' 及 `-W' 选项都有正反两种形式：-fname 及
-fno-name (或 -Wname 及 -Wno-name)。以下只列出非预设的那个
形式。
以下是所有选项的摘要。以形式来分类。选项的意义将另辟小节说
明。
一般性(概略、常用的)选项
-c -S -E -o file -pipe -v -x language
程序语言选项
-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
编译时的警告选项
-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
除错选项
-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
最佳化选项
-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
预处理选项
-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
汇编程序选项
-Wa,option
连结程序选项
-llibrary -nostartfiles -nostdlib -static -shared
-symbolic -Xlinker option -Wl,option -u symbol
目录选项
-Bprefix -Idir -I- -Ldir
Target Options
-b machine -V version
与机器(平台)相关的选项
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 want
a single implementation file to include code from
multiple header files.
There is no way to split up the contents of a sin-
gle header file into multiple implementation files.
文件说明
file.c C source file
file.h C header (preprocessor) file
file.i 经预处理过的 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, 参阅 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).