Assigning the value from the void pointer to a non void pointer

Question

I have a situation where in the address inside the void pointer to be copied to a another pointer. Doing this without a type cast gives no warnings or errors. The pseudo code looks like

structA A;
void * p = &A;
structA * B = p;// Would like to conform this step

I don't foresee any problems with this. But since this operation is used over a lot of places, I would like to conform whether it can have any replications. Also is there any compiler dependency?

See http://stackoverflow.com/questions/15745030/type-punning-with-void-without-breaking-the-strict-aliasing-rule-in-c99 — Pavel Šimerda, Apr 02 '14 at 08:54
"Conform whether it has replications"? Why not use simple English: "I would like to check whether it works." — Kerrek SB, Apr 02 '14 at 08:58
I had tested this with some pseudo code and it works ok. Still the question was intended to conform there is no possibility of any hidden issues.....Sorry if that had cause a confusion — Ginu Jacob, Apr 02 '14 at 09:05

score 5 · Accepted Answer · edited May 23 '17 at 12:20

5

No, this is fine and 100% standard.

A void * can be converted to and from any other data/object pointer without problems.

Note that data/object restriction: function pointers do not convert to/from void *.

This is the reason why you shouldn't cast the return value of malloc(), which returns a void *.

edited May 23 '17 at 12:20

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answered Apr 02 '14 at 08:55

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score 1 · Answer 2 · answered Apr 02 '14 at 08:56

In C a void * is implicitly compatible with any pointer. That why you don't need to cast when e.g. passing pointers of any type to functions taking void * arguments, or when assigning to pointer (still of any type) from function returning void * (here malloc is a good example).

Assigning the value from the void pointer to a non void pointer

2 Answers2