此事需求的来源是有要求调查，gcc中的那些warning是有问题的，代码必须要修改，那些事需要确认的，就要显示所有的warning选项是什么
查了下，方法如下
显示所有的warning和warning的激活状态
gcc -Q --help=warning
显示所有的all, extra和warning的激活状态
gcc -Wall -Wextra -Q --help=warning
显示所有的warning list
gcc -Q --help=warning | sed -e 's/^s*(-S*)s*[w*]/1 /gp;d' | tr -d '
'
warning list
-Wabi -Wabi-tag -Waddress -Waggregate-return -Waggressive-loop-optimizations -Warray-bounds -Wassign-intercept -Wattributes -Wbad-function-cast -Wc++-compat -Wc++0x-compat -Wcast-align -Wcast-qual -Wcast-result -Wchar-subscripts -Wclobbered -Wconversion -Wconversion-null -Wcoverage-mismatch -Wcpp -Wctor-dtor-privacy -Wdeclaration-after-statement -Wdelete-non-virtual-dtor -Wdeprecated -Wdeprecated-declarations -Wdisabled-optimization -Wdiv-by-zero -Wdouble-promotion -Weffc++ -Wempty-body -Wenum-compare -Wextra -Wfloat-equal -Wformat-contains-nul -Wformat-extra-args -Wformat-nonliteral -Wformat-security -Wformat-y2k -Wformat-zero-length -Wfree-nonheap-object -Wignored-qualifiers -Wimplicit -Wimplicit-function-declaration -Wimplicit-int -Winherited-variadic-ctor -Winit-self -Winline -Wint-to-pointer-cast -Winvalid-memory-model -Winvalid-offsetof -Wjump-misses-init -Wlogical-op -Wlong-long -Wmain -Wmaybe-uninitialized -Wmissing-braces -Wmissing-declarations -Wmissing-field-initializers -Wmissing-parameter-type -Wmissing-prototypes -Wmudflap -Wnarrowing -Wnested-externs -Wnoexcept -Wnon-template-friend -Wnon-virtual-dtor -Wnonnull -Wold-style-cast -Wold-style-declaration -Wold-style-definition -Woverflow -Woverlength-strings -Woverloaded-virtual -Woverride-init -Wpacked -Wpacked-bitfield-compat -Wpadded -Wparentheses -Wpedantic -Wpmf-conversions -Wpointer-arith -Wpointer-sign -Wpointer-to-int-cast -Wpragmas -Wproperty-assign-default -Wprotocol -Wredundant-decls -Wreorder -Wreturn-local-addr -Wreturn-type -Wselector -Wsequence-point -Wshadow -Wsign-compare -Wsign-promo -Wsizeof-pointer-memaccess -Wstack-protector -Wstrict-null-sentinel -Wstrict-prototypes -Wstrict-selector-match -Wsuggest-attribute=const -Wsuggest-attribute=format -Wsuggest-attribute=noreturn -Wsuggest-attribute=pure -Wswitch -Wswitch-default -Wswitch-enum -Wsync-nand -Wsynth -Wsystem-headers -Wtraditional -Wtraditional-conversion -Wtrampolines -Wtype-limits -Wundeclared-selector -Wuninitialized -Wunknown-pragmas -Wunsafe-loop-optimizations -Wunsuffixed-float-constants -Wunused -Wunused-but-set-parameter -Wunused-but-set-variable -Wunused-function -Wunused-label -Wunused-local-typedefs -Wunused-macros -Wunused-parameter -Wunused-result -Wunused-value -Wunused-variable -Wuseless-cast -Wvarargs -Wvariadic-macros -Wvector-operation-performance -Wvirtual-move-assign -Wvla -Wvolatile-register-var -Wwrite-strings -Wzero-as-null-pointer-constant -frequire-return-statement