"warning: use of old-style cast" in g++

Question

Possible Duplicate:
When should static_cast, dynamic_cast and reinterpret_cast be used?

With this C++ code,

char* a = (char*) b;

I got warning warning: use of old-style cast.

What would be the new-style cast?

score 69 · Accepted Answer · edited Apr 24 '20 at 17:01

reinterpret_cast, static_cast, dynamic_cast and const_cast are the c++ cast alternatives.

const_cast to remove const/volatile from a const variable.
dynamic_cast to perform runtime validity checks when casting in between polymorphic types
static_cast to perform e.g up/down-cast in a inheritance hierarchy, but with no runtime checks, or to explicitly perform conversions that could be implicit (e.g. float to int)
reinterpret_cast to convert in between unrelated types.

Brief syntax example:

char* a = (char*) b; 
//would be 
char* a = static_cast<char*>(b);
//to remove the warning

score 3 · Answer 2 · edited May 23 '17 at 10:30

3

Read this topic to know about C++ style casts which come in various flavors:

edited May 23 '17 at 10:30

Community

answered Mar 09 '11 at 17:09

Nawaz

3

I would argue that, if you think a link to another question is a suitable answer, then the question is a duplicate. – Chris Lutz Mar 09 '11 at 17:10
@Chris: After posting, I realized that. So I voted for closing it! – Nawaz Mar 09 '11 at 17:11
1

Depends, could he find the other question by searching for "old-style" and/or "new-style" cast? – Erik Mar 09 '11 at 17:12
2

@Erik: it doesn't depend, since if this question is marked a duplicate, it still stands as a search landing page. If it's a dupe, it should be marked a dupe, not answered again with identical answers just because the question is worded a bit differently. – Steve Jessop Mar 09 '11 at 17:24
Ahh ok, then I'll vote to close as well. – Erik Mar 09 '11 at 17:25

2 Answers2