cc: add two new #pragma varargck
#pragma varargck countpos f 1
says that the first argument to f is
the count of variadic arguments that follow.
#pragma varargck type f t
says that t is one of the allowed types for
a variadic argument to f.
(can be repeated)
combined, these can be used to check the
runtime.stdcall functions in the windows port
or in any other port that needs a vararg list of
uintptrs even on a 64-bit platform (where it is
very easy to pass a less-than-uintptr in the ...).
demo:
typedef unsigned int uintptr;
#pragma varargck countpos f 1
#pragma varargck type f uintptr
#pragma varargck type f void*
int f(int count, ...);
void *v;
char *p;
void
main(void)
{
f(1, v); // ok
f(1, main); // ok
f(1, p); // ok
f(2, v, v); // ok
f(2, v); // found 1 argument after count 2
f(1, 'a'); // invalid type INT in call to f
f(1, 0); // invalid type INT in call to f
}
R=ken, r, alex.brainman
CC=golang-dev
https://golang.org/cl/
4634103