At least one type specifier shall be given in the declaration specifiers in each declaration. See also D.1.6 Disallowed Implicit int and Implicit Function Declarations.
The C compiler now issues warnings on any implicit int declaration as in the following example:
example% more test.c volatile i; const foo() { return i; } example% cc test.c "test.c", line 1: warning: no explicit type given "test.c", line 3: warning: no explicit type given example% |