Using a pointer variable typedef

Question

I define a typedef

typedef char* charP;

Then I declare a few variables

charP dog, cat, fish;

Are all the variables of type char* or is dog the only char* while cat and fish are of type char?

printf("%d %d %d\n", sizeof dog, sizeof cat, sizeof fish); would have given you the answer in an instant. — glglgl
– glglgl, Commented Jul 7, 2014 at 11:23
@glglgl The proper formatting code for values of type size_t is %zu. — unwind
– unwind, Commented Jul 7, 2014 at 11:30
@unwind While you are completely right, for a quick test it should work as well. But there is a chance that I run into trouble with that, so better do it right your way. But then I'd have to lookup the z, and I hadn't the answer in an instant, but in several minutes :-} — glglgl
– glglgl, Commented Jul 7, 2014 at 11:33

unwind · Accepted Answer · 2014-07-07 11:22:01Z

10

All of them are of type charP, which is an alias for char *, so yes, they're all pointers.

That said, some people (me included) consider it a bad idea to "hide" the pointer asterisk, since it breaks the symmetry between declaring the variable and accessing it.

You're going to have:

charP a;

*a = '1';  /* What?! It didn't look like a pointer, above?! */

... which causes confusion. Generally, pointers in C are important to keep track of, so hiding what is a pointer and what isn't can lead to trouble.

answered Jul 7, 2014 at 11:22

unwind

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2 Comments

unwind Over a year ago

@Quentin Yeah, I don't quite ... agree that those were ever a good idea. :)

Deduplicator Over a year ago

Well, MS loves the Macros and typedefs, some of them even make sense because they hint at semantics (like BSTR). Would be nice if they changed to standard types where possible someday, though...

sampathsris · Accepted Answer · 2014-07-07 11:53:24Z

1

All of them are char *. Do not confuse it with this case: char *dog, cat, fish;. Here, dog is a char *, and rest are just chars.

answered Jul 7, 2014 at 11:53

sampathsris

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Comments

PU. · Accepted Answer · 2014-07-07 12:28:26Z

0

All of them are char pointers as you are using typedef and not macro.

so it will not behave like char *dog, cat, fish;

answered Jul 7, 2014 at 12:28

PU.

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