GCC supports a plethora of ISO standards, language extensions, pragmas, etc. It simply isn’t tractable to guarantee support for every behavior or language const

GCC supports a plethora of ISO standards, language extensions, pragmas, etc. It simply isn’t tractable to guarantee support for every behavior or language construct which GCC has tacitly supported. Compilers like GCC may go above and beyond the ISO C standards, but they aren’t in the business of supporting every C dialect possible.