GCC是每个从事Linux，以及嵌入式开发等必备的编译器，由于帮助手册较多，这里使用了分页的形式进行分享，如下为Ubuntu Server 22.04操作系统平台。

GCC帮助手册的第6小节，第947~1247行。

947           Objective-C++) that the compiler accepts:948           -ansi949               In C mode, this is equivalent to -std=c90. In C++ mode, it is equivalent to -std=c++98.950               This turns off certain features of GCC that are incompatible with ISO C90 (when compiling C code), or of951               standard C++ (when compiling C++ code), such as the "asm" and "typeof" keywords, and predefined macros such952               as "unix" and "vax" that identify the type of system you are using.  It also enables the undesirable and953               rarely used ISO trigraph feature.  For the C compiler, it disables recognition of C++ style // comments as954               well as the "inline" keyword.955               The alternate keywords "__asm__", "__extension__", "__inline__" and "__typeof__" continue to work despite956               -ansi.  You would not want to use them in an ISO C program, of course, but it is useful to put them in957               header files that might be included in compilations done with -ansi.  Alternate predefined macros such as958               "__unix__" and "__vax__" are also available, with or without -ansi.959               The -ansi option does not cause non-ISO programs to be rejected gratuitously.  For that, -Wpedantic is960               required in addition to -ansi.961               The macro "__STRICT_ANSI__" is predefined when the -ansi option is used.  Some header files may notice this962               macro and refrain from declaring certain functions or defining certain macros that the ISO standard doesn't963               call for; this is to avoid interfering with any programs that might use these names for other things.964               Functions that are normally built in but do not have semantics defined by ISO C (such as "alloca" and965               "ffs") are not built-in functions when -ansi is used.966           -std=967               Determine the language standard.   This option is currently only supported when compiling C or C++.968               The compiler can accept several base standards, such as c90 or c++98, and GNU dialects of those standards,969               such as gnu90 or gnu++98.  When a base standard is specified, the compiler accepts all programs following970               that standard plus those using GNU extensions that do not contradict it.  For example, -std=c90 turns off971               certain features of GCC that are incompatible with ISO C90, such as the "asm" and "typeof" keywords, but972               not other GNU extensions that do not have a meaning in ISO C90, such as omitting the middle term of a "?:"973               expression. On the other hand, when a GNU dialect of a standard is specified, all features supported by the974               compiler are enabled, even when those features change the meaning of the base standard.  As a result, some975               strict-conforming programs may be rejected.  The particular standard is used by -Wpedantic to identify976               which features are GNU extensions given that version of the standard. For example -std=gnu90 -Wpedantic977               warns about C++ style // comments, while -std=gnu99 -Wpedantic does not.978               A value for this option must be provided; possible values are979               c90980               c89981               iso9899:1990982                   Support all ISO C90 programs (certain GNU extensions that conflict with ISO C90 are disabled). Same as983                   -ansi for C code.984               iso9899:199409985                   ISO C90 as modified in amendment 1.986               c99987               c9x988               iso9899:1999989               iso9899:199x990                   ISO C99.  This standard is substantially completely supported, modulo bugs and floating-point issues991                   (mainly but not entirely relating to optional C99 features from Annexes F and G).  See992                   <; for more information.  The names c9x and iso9899:199x are993                   deprecated.994               c11995               c1x996               iso9899:2011997                   ISO C11, the 2011 revision of the ISO C standard.  This standard is substantially completely supported,998                   modulo bugs, floating-point issues (mainly but not entirely relating to optional C11 features from999                   Annexes F and G) and the optional Annexes K (Bounds-checking interfaces) and L (Analyzability).  The1000                  name c1x is deprecated.1001              c171002              c181003              iso9899:20171004              iso9899:20181005                  ISO C17, the 2017 revision of the ISO C standard (published in 2018).  This standard is same as C111006                  except for corrections of defects (all of which are also applied with -std=c11) and a new value of1007                  "__STDC_VERSION__", and so is supported to the same extent as C11.1008              c2x The next version of the ISO C standard, still under development.  The support for this version is1009                  experimental and incomplete.1010              gnu901011              gnu891012                  GNU dialect of ISO C90 (including some C99 features).1013              gnu991014              gnu9x1015                  GNU dialect of ISO C99.  The name gnu9x is deprecated.1016              gnu111017              gnu1x1018                  GNU dialect of ISO C11.  The name gnu1x is deprecated.1019              gnu171020              gnu181021                  GNU dialect of ISO C17.  This is the default for C code.1022              gnu2x1023                  The next version of the ISO C standard, still under development, plus GNU extensions.  The support for1024                  this version is experimental and incomplete.1025              c++981026              c++031027                  The 1998 ISO C++ standard plus the 2003 technical corrigendum and some additional defect reports. Same1028                  as -ansi for C++ code.1029              gnu++981030              gnu++031031                  GNU dialect of -std=c++98.1032              c++111033              c++0x1034                  The 2011 ISO C++ standard plus amendments.  The name c++0x is deprecated.1035              gnu++111036              gnu++0x1037                  GNU dialect of -std=c++11.  The name gnu++0x is deprecated.1038              c++141039              c++1y1040                  The 2014 ISO C++ standard plus amendments.  The name c++1y is deprecated.1041              gnu++141042              gnu++1y1043                  GNU dialect of -std=c++14.  The name gnu++1y is deprecated.1044              c++171045              c++1z1046                  The 2017 ISO C++ standard plus amendments.  The name c++1z is deprecated.1047              gnu++171048              gnu++1z1049                  GNU dialect of -std=c++17.  This is the default for C++ code.  The name gnu++1z is deprecated.1050              c++201051              c++2a1052                  The 2020 ISO C++ standard plus amendments.  Support is experimental, and could change in incompatible1053                  ways in future releases.  The name c++2a is deprecated.1054              gnu++201055              gnu++2a1056                  GNU dialect of -std=c++20.  Support is experimental, and could change in incompatible ways in future1057                  releases.  The name gnu++2a is deprecated.1058              c++2b1059              c++231060                  The next revision of the ISO C++ standard, planned for 2023.  Support is highly experimental, and will1061                  almost certainly change in incompatible ways in future releases.1062              gnu++2b1063              gnu++231064                  GNU dialect of -std=c++2b.  Support is highly experimental, and will almost certainly change in1065                  incompatible ways in future releases.1066          -fgnu89-inline1067              The option -fgnu89-inline tells GCC to use the traditional GNU semantics for "inline" functions when in C991068              mode.1069              Using this option is roughly equivalent to adding the "gnu_inline" function attribute to all inline1070              functions.1071              The option -fno-gnu89-inline explicitly tells GCC to use the C99 semantics for "inline" when in C99 or1072              gnu99 mode (i.e., it specifies the default behavior).  This option is not supported in -std=c90 or1073              -std=gnu90 mode.1074              The preprocessor macros "__GNUC_GNU_INLINE__" and "__GNUC_STDC_INLINE__" may be used to check which1075              semantics are in effect for "inline" functions.1076          -fpermitted-flt-eval-methods=style1077              ISO/IEC TS 18661-3 defines new permissible values for "FLT_EVAL_METHOD" that indicate that operations and1078              constants with a semantic type that is an interchange or extended format should be evaluated to the1079              precision and range of that type.  These new values are a superset of those permitted under C99/C11, which1080              does not specify the meaning of other positive values of "FLT_EVAL_METHOD".  As such, code conforming to1081              C11 may not have been written expecting the possibility of the new values.1082              -fpermitted-flt-eval-methods specifies whether the compiler should allow only the values of1083              "FLT_EVAL_METHOD" specified in C99/C11, or the extended set of values specified in ISO/IEC TS 18661-3.1084              style is either "c11" or "ts-18661-3" as appropriate.1085              The default when in a standards compliant mode (-std=c11 or similar) is -fpermitted-flt-eval-methods=c11.1086              The default when in a GNU dialect (-std=gnu11 or similar) is -fpermitted-flt-eval-methods=ts-18661-3.1087          -aux-info filename1088              Output to the given filename prototyped declarations for all functions declared and/or defined in a1089              translation unit, including those in header files.  This option is silently ignored in any language other1090              than C.1091              Besides declarations, the file indicates, in comments, the origin of each declaration (source file and1092              line), whether the declaration was implicit, prototyped or unprototyped (I, N for new or O for old,1093              respectively, in the first character after the line number and the colon), and whether it came from a1094              declaration or a definition (C or F, respectively, in the following character).  In the case of function1095              definitions, a K&R-style list of arguments followed by their declarations is also provided, inside1096              comments, after the declaration.1097          -fallow-parameterless-variadic-functions1098              Accept variadic functions without named parameters.1099              Although it is possible to define such a function, this is not very useful as it is not possible to read1100              the arguments.  This is only supported for C as this construct is allowed by C++.1101          -fno-asm1102              Do not recognize "asm", "inline" or "typeof" as a keyword, so that code can use these words as identifiers.1103              You can use the keywords "__asm__", "__inline__" and "__typeof__" instead.  -ansi implies -fno-asm.1104              In C++, this switch only affects the "typeof" keyword, since "asm" and "inline" are standard keywords.  You1105              may want to use the -fno-gnu-keywords flag instead, which has the same effect.  In C99 mode (-std=c99 or1106              -std=gnu99), this switch only affects the "asm" and "typeof" keywords, since "inline" is a standard keyword1107              in ISO C99.1108          -fno-builtin1109          -fno-builtin-function1110              Don't recognize built-in functions that do not begin with __builtin_ as prefix.1111              GCC normally generates special code to handle certain built-in functions more efficiently; for instance,1112              calls to "alloca" may become single instructions which adjust the stack directly, and calls to "memcpy" may1113              become inline copy loops.  The resulting code is often both smaller and faster, but since the function1114              calls no longer appear as such, you cannot set a breakpoint on those calls, nor can you change the behavior1115              of the functions by linking with a different library.  In addition, when a function is recognized as a1116              built-in function, GCC may use information about that function to warn about problems with calls to that1117              function, or to generate more efficient code, even if the resulting code still contains calls to that1118              function.  For example, warnings are given with -Wformat for bad calls to "printf" when "printf" is built1119              in and "strlen" is known not to modify global memory.1120              With the -fno-builtin-function option only the built-in function function is disabled.  function must not1121              begin with __builtin_.  If a function is named that is not built-in in this version of GCC, this option is1122              ignored.  There is no corresponding -fbuiltin-function option; if you wish to enable built-in functions1123              selectively when using -fno-builtin or -ffreestanding, you may define macros such as:1124                      #define abs(n)          __builtin_abs ((n))1125                      #define strcpy(d, s)    __builtin_strcpy ((d), (s))1126          -fgimple1127              Enable parsing of function definitions marked with "__GIMPLE".  This is an experimental feature that allows1128              unit testing of GIMPLE passes.1129          -fhosted1130              Assert that compilation targets a hosted environment.  This implies -fbuiltin.  A hosted environment is one1131              in which the entire standard library is available, and in which "main" has a return type of "int".1132              Examples are nearly everything except a kernel.  This is equivalent to -fno-freestanding.1133          -ffreestanding1134              Assert that compilation targets a freestanding environment.  This implies -fno-builtin.  A freestanding1135              environment is one in which the standard library may not exist, and program startup may not necessarily be1136              at "main".  The most obvious example is an OS kernel.  This is equivalent to -fno-hosted.1137          -fopenacc1138              Enable handling of OpenACC directives "#pragma acc" in C/C++ and "!$acc" in Fortran.  When -fopenacc is1139              specified, the compiler generates accelerated code according to the OpenACC Application Programming1140              Interface v2.6 <;.  This option implies -pthread, and thus is only supported on1141              targets that have support for -pthread.1142          -fopenacc-dim=geom1143              Specify default compute dimensions for parallel offload regions that do not explicitly specify.  The geom1144              value is a triple of ':'-separated sizes, in order 'gang', 'worker' and, 'vector'.  A size can be omitted,1145              to use a target-specific default value.1146          -fopenmp1147              Enable handling of OpenMP directives "#pragma omp" in C/C++ and "!$omp" in Fortran.  When -fopenmp is1148              specified, the compiler generates parallel code according to the OpenMP Application Program Interface v4.51149              <;.  This option implies -pthread, and thus is only supported on targets that have1150              support for -pthread. -fopenmp implies -fopenmp-simd.1151          -fopenmp-simd1152              Enable handling of OpenMP's SIMD directives with "#pragma omp" in C/C++ and "!$omp" in Fortran. Other1153              OpenMP directives are ignored.1154          -fgnu-tm1155              When the option -fgnu-tm is specified, the compiler generates code for the Linux variant of Intel's current1156              Transactional Memory ABI specification document (Revision 1.1, May 6 2009).  This is an experimental1157              feature whose interface may change in future versions of GCC, as the official specification changes.1158              Please note that not all architectures are supported for this feature.1159              For more information on GCC's support for transactional memory,1160              Note that the transactional memory feature is not supported with non-call exceptions1161              (-fnon-call-exceptions).1162          -fms-extensions1163              Accept some non-standard constructs used in Microsoft header files.1164              In C++ code, this allows member names in structures to be similar to previous types declarations.1165                      typedef int UOW;1166                      struct ABC {1167                        UOW UOW;1168                      };1169              Some cases of unnamed fields in structures and unions are only accepted with this option.1170              Note that this option is off for all targets except for x86 targets using ms-abi.1171          -fplan9-extensions1172              Accept some non-standard constructs used in Plan 9 code.1173              This enables -fms-extensions, permits passing pointers to structures with anonymous fields to functions1174              that expect pointers to elements of the type of the field, and permits referring to anonymous fields1175              declared using a typedef.    This is only supported for C, not C++.1176          -fcond-mismatch1177              Allow conditional expressions with mismatched types in the second and third arguments.  The value of such1178              an expression is void.  This option is not supported for C++.1179          -flax-vector-conversions1180              Allow implicit conversions between vectors with differing numbers of elements and/or incompatible element1181              types.  This option should not be used for new code.1182          -funsigned-char1183              Let the type "char" be unsigned, like "unsigned char".1184              Each kind of machine has a default for what "char" should be.  It is either like "unsigned char" by default1185              or like "signed char" by default.1186              Ideally, a portable program should always use "signed char" or "unsigned char" when it depends on the1187              signedness of an object.  But many programs have been written to use plain "char" and expect it to be1188              signed, or expect it to be unsigned, depending on the machines they were written for.  This option, and its1189              inverse, let you make such a program work with the opposite default.1190              The type "char" is always a distinct type from each of "signed char" or "unsigned char", even though its1191              behavior is always just like one of those two.1192          -fsigned-char1193              Let the type "char" be signed, like "signed char".1194              Note that this is equivalent to -fno-unsigned-char, which is the negative form of -funsigned-char.1195              Likewise, the option -fno-signed-char is equivalent to -funsigned-char.1196          -fsigned-bitfields1197          -funsigned-bitfields1198          -fno-signed-bitfields1199          -fno-unsigned-bitfields1200              These options control whether a bit-field is signed or unsigned, when the declaration does not use either1201              "signed" or "unsigned".  By default, such a bit-field is signed, because this is consistent: the basic1202              integer types such as "int" are signed types.1203          -fsso-struct=endianness1204              Set the default scalar storage order of structures and unions to the specified endianness.  The accepted1205              values are big-endian, little-endian and native for the native endianness of the target (the default).1206              This option is not supported for C++.1207              Warning: the -fsso-struct switch causes GCC to generate code that is not binary compatible with code1208              generated without it if the specified endianness is not the native endianness of the target.1209      Options Controlling C++ Dialect1210          This section describes the command-line options that are only meaningful for C++ programs.  You can also use1211          most of the GNU compiler options regardless of what language your program is in.  For example, you might1212          compile a file firstClass.C like this:1213                  g++ -g -fstrict-enums -O -c firstClass.C1214          In this example, only -fstrict-enums is an option meant only for C++ programs; you can use the other options1215          with any language supported by GCC.1216          Some options for compiling C programs, such as -std, are also relevant for C++ programs.1217          Here is a list of options that are only for compiling C++ programs:1218          -fabi-version=n1219              Use version n of the C++ ABI.  The default is version 0.1220              Version 0 refers to the version conforming most closely to the C++ ABI specification.  Therefore, the ABI1221              obtained using version 0 will change in different versions of G++ as ABI bugs are fixed.1222              Version 1 is the version of the C++ ABI that first appeared in G++ 3.2.1223              Version 2 is the version of the C++ ABI that first appeared in G++ 3.4, and was the default through G++1224              4.9.1225              Version 3 corrects an error in mangling a constant address as a template argument.1226              Version 4, which first appeared in G++ 4.5, implements a standard mangling for vector types.1227              Version 5, which first appeared in G++ 4.6, corrects the mangling of attribute const/volatile on function1228              pointer types, decltype of a plain decl, and use of a function parameter in the declaration of another1229              parameter.1230              Version 6, which first appeared in G++ 4.7, corrects the promotion behavior of C++11 scoped enums and the1231              mangling of template argument packs, const/static_cast, prefix ++ and --, and a class scope function used1232              as a template argument.1233              Version 7, which first appeared in G++ 4.8, that treats nullptr_t as a builtin type and corrects the1234              mangling of lambdas in default argument scope.1235              Version 8, which first appeared in G++ 4.9, corrects the substitution behavior of function types with1236              function-cv-qualifiers.1237              Version 9, which first appeared in G++ 5.2, corrects the alignment of "nullptr_t".1238              Version 10, which first appeared in G++ 6.1, adds mangling of attributes that affect type identity, such as1239              ia32 calling convention attributes (e.g. stdcall).1240              Version 11, which first appeared in G++ 7, corrects the mangling of sizeof... expressions and operator1241              names.  For multiple entities with the same name within a function, that are declared in different scopes,1242              the mangling now changes starting with the twelfth occurrence.  It also implies -fnew-inheriting-ctors.1243              Version 12, which first appeared in G++ 8, corrects the calling conventions for empty classes on the x86_641244              target and for classes with only deleted copy/move constructors.  It accidentally changes the calling1245              convention for classes with a deleted copy constructor and a trivial move constructor.1246              Version 13, which first appeared in G++ 8.2, fixes the accidental change in version 12.1247              Version 14, which first appeared in G++ 10, corrects the mangling of the nullptr expression.