[E6300]

1. Unless C's variable definition rules are completely different from C++'s, int i; is a full definition, not a declaration. If both definitions appear at the same scope (e.g. global), this will cause either a compiler error or a linker error. A variable declaration would be extern int i;

[khedoros1]

C's variable definition rules are different from C++'s. gcc happily compiles those two lines, g++ exits with the "redefinition" error.

[caf]

Yes, in C a plain

  int i;

at file scope is a tentative definition - if, by the end of the compilation unit, no definition has been seen, one of them will become a definition, otherwise it is just a declaration.

On the other hand, this:

  int i = 0;

is a definition, and you can't have two of those.

[E6300]

That was unexpected.

[shabbyrobe]

Said every C programmer ever!