GCC Warnings:

‘-Wall’ turns on the following warning flags:

-Waddress
-Warray-bounds (only with ‘-O2’)
-Wc++11-compat
-Wchar-subscripts
-Wenum-compare (in C/ObjC; this is on by default in C++) -Wimplicit-int (C and Objective-C only) -Wimplicit-function-declaration (C and Objective-C only) -Wcomment
-Wformat
-Wmain (only for C/ObjC and unless ‘-ffreestanding’) -Wmaybe-uninitialized
-Wmissing-braces (only for C/ObjC)
-Wnonnull
-Wparentheses
-Wpointer-sign
-Wreorder
-Wreturn-type
-Wsequence-point
-Wsign-compare (only in C++)
-Wstrict-aliasing
-Wstrict-overflow=1
-Wswitch
-Wtrigraphs
-Wuninitialized
-Wunknown-pragmas
-Wunused-function
-Wunused-label
-Wunused-value
-Wunused-variable
-Wvolatile-register-var

‘-Wextra’ turns on the following warning flags:

-Wclobbered
-Wempty-body 
-Wignored-qualifiers 
-Wmissing-field-initializers 
-Wmissing-parameter-type (C only) 
-Wold-style-declaration (C only) 
-Woverride-init
-Wsign-compare
-Wtype-limits
-Wuninitialized
-Wunused-parameter (only with ‘-Wunused’ or ‘-Wall’) 
-Wunused-but-set-parameter (only with ‘-Wunused’ or ‘-Wall’)
