On Tue, Jan 17, 2017 at 4:36 PM, Jonathan Wakely <jwakely.gcc@xxxxxxxxx> wrote: > On 17 January 2017 at 11:03, vijay nag wrote: >> Hello Gcc, >> >> I came across this nasty C code of an enumerator and a macro having >> the same name. Although this is a buggy code, I found it surprising >> that GCC compiles in one of the cases(snippet 1) while in the other >> compiler flags an error(snippet 2). Would be interested to know why >> the order of definitions/declarations matter and what C standards the >> compiler is adhering to ? > > Just look at the preprocessed code, it should be obvious. > > Macros aren't defined until they're defined. > > When the macro is defined after the enumerator it can't change it and > you get a valid enumerator definition, FOO = 1. > > When the macro is defined earlier it produces an invalid enumerator, > 0xDEADBEEF = 1 > > What isn't clear? Thanks for the reply, it is clear now. So, can enum have same name as that of a macro and Is it allowed in C ?
