I implemented a secure printf_s and its API is the problem. You cannot dead-code...

bobmcnamara · on April 27, 2025

The only hack I could think of is having the compiler front end generate calls to different functions based on the content of the format string, similar to how some compilers replace memset with a 32-bit memset based on the type of the destination pointer

And it all falls apart as soon as a format string cannot be known at compile time.

Someone · on April 27, 2025

> The only hack I could think of is having the compiler front end generate calls to different functions based on the content of the format string

Compilers do that, at least for the simple case of constant strings; gcc can compile a printf call as puts. See https://stackoverflow.com/questions/60080021/compiler-change...

bobmcnamara · on April 28, 2025

That's the only one I've ever seen, and it's really just checking for the absence of '%'.

What if it could convert:

printf("parsed: %s to %i\n", x, y);

To:

puts("parsed: "); puts(x); puts(" to "); _puti(y); putc('\n');

Well. Then we'd have a lot more function calls overhead. Maybe something like:

_printf_nofloat("parsed: %s to %i\n", x, y);

Someone · on April 28, 2025

It’s not the only one it uses.

It also removes calls to printf("") and changes single character printf calls to putchar calls

See https://github.com/gcc-mirror/gcc/blob/ef32bd8c866a1b8a97f62...