Function overloading in C++

MTK358 · 06-10-2010, 10:19 AM

Quote:

Originally Posted by tuxdev

It's not type-safe at all. GCC tries to give you pseudo-typesafeness warning, but it's completely optional. Stream insertion will always to the "Right Thing", as defined by the << overload for that type.

Does that really matter unless you're so dumb that you keep typing the wrong letters after the '%'?

JohnGraham · 06-10-2010, 12:23 PM

Quote:

Originally Posted by MTK358

Does that really matter unless you're so dumb that you keep typing the wrong letters after the '%'?

To be fair, anyone can make mistakes - you change an int to a long because you need a wider data type, and forget to change all the printf's it's in. Easily done.

Quote:

GCC tries to give you pseudo-typesafeness warning, but it's completely optional.

It's not optional at all - you could probably opt out of it with -Wno-<something>, but that's just asking for trouble:

Code:

$ cat test.c
#include <stdio.h>

int main(void)
{
    long i = 5;
    printf("%d\n", i);
    return 0;
}

$ make test
cc     test.c   -o test
test.c: In function ‘main’:
test.c:6: warning: format ‘%d’ expects type ‘int’, but argument 2 has type ‘long int’

("Look, no options!"

)

posixculprit · 06-10-2010, 12:29 PM

Quote:

Originally Posted by MTK358

What's so bad about printf()?

Nothing. This is also irrelevant to the matter that was being discussed.

tuxdev · 06-10-2010, 01:03 PM

Quote:

It's not optional at all - you could probably opt out of it with -Wno-<something>, but that's just asking for trouble:

Sorry, I meant "optional" as in "not required by the standard". Other compilers won't be so nice.

Sergei Steshenko · 06-10-2010, 03:44 PM

Quote:

Originally Posted by MTK358

...Does that really matter unless you're so dumb that you keep typing the wrong letters after the '%'?

The dumbest thing a programmer can do is thinking of his/herself as being smart.

MTK358 · 06-10-2010, 04:10 PM

Quote:

Originally Posted by Sergei Steshenko

The dumbest thing a programmer can do is thinking of his/herself as being smart.

That's not what I meant.

I meant that as long as you put in the right letters, it's impossible for something bad to happen, even if operating on user input.

Sergei Steshenko · 06-10-2010, 04:38 PM

Quote:

Originally Posted by MTK358

That's not what I meant.

I meant that as long as you put in the right letters, it's impossible for something bad to happen, even if operating on user input.

You are not getting it - the right/wrong letters are better seen by compiler, and sometimes a variable "changes type", i.e. initially a programmer thinks he/she needs 'int', but then changes it to 'short' or 'long', but the programmer forgets to change the corresponding format specification in 'printf'.

My point is: absolutely never think you wont' make a mistake, always think you will, and use compiler to point out all possible stupid things you could think/make.

JohnGraham · 06-10-2010, 05:22 PM

Quote:

Originally Posted by MTK358

I meant that as long as you put in the right letters, it's impossible for something bad to happen, even if operating on user input.

That's true.

However, you're assuming that programmers are infallible, and that's an assumption that every programmer I know (including - no, especially - myself) disproves on a regular basis.

For once, I agree with Sergei - please don't assume you'll always get it right just because it's easy, or that you won't change something in a project a few thousand lines long and fail to change every single instance of anything that's been affected by it.