Parenthesis surrounding return values

Question

Quite often in ANSI C code I can see parenthesis sorrounding a single return value.

Like this:-

int foo(int x) {
  if (x)
    return (-1);
  else
    return (0);
}

Why use () around the return value in those cases? Any ideas? I can see no reason for that.

Answer 1

As often the case when using parenthesis I think that's just for readability (Ruby supports method calls w/o parenthesis enclosing the arguments but recent books and articles advice otherwhise).

Answer 2

There really isn't a reason...it's just old convention.

To save space, programmers would often to final math in the return like, like this:

return (x+i*2);

The parenthesis became a habit and it stuck.

Answer 3

Perhaps this is because with parenthesis it is looking more like a function call, i.e. looking more like the rest of the code?

Or its just something everybody does, just because everybody else does it :-)

Answer 4

My personal style is to use parentheses if there is a complex expression; e.g.,

return (a + b);

but to not use them if the expression is a simple term

return a;

I can't say why I do it that way; just something I picked up long ago.

By the way, I think that making it look like a function call, like this:

return(a);  // ugh

is incredibly ugly and just wrong.

Answer 5

There are a few reasons:

1. if/while/for/etc. are all control keywords which must have parens. So it often seems natural to always put them on return too.

2. sizeof is the only other keyword that can either have them or not, except that in some cases you must use parens. So it's easier to get into the habit of always using parens. for sizeof, which implies a logic of: if you can, always do.

3. case/goto are the only keywords where you never use parens. ... and people tend to think of those as special cases (and like them both to stand out from other control keywords, esp. goto).

Answer 6

A practical, but unlikely, motive is if you put parenthesis around the value, you can define return as a macro, and then insert some logging code to watch all your returns.

Answer 7

I've worked with at least one programmer who thought return was some special sort of function call, and was suprised when he saw that my code complied without the parens.

Answer 8

When returning -1 as in your excample, I think it's more readable with the parenthesis because the minus is more visible:

return 1

or

return -1

or

return (-1)