Re: const char *

On Friday 6 August 2010 14:43:31 Rich Mattes wrote:
> It looks like the compiler is treating "crabbing" as a const-qualified
> string.  Since none of the set/get functions are expected to modify the
> key string you pass, it seems sane to modify all of them to accept
> const arguments (this guarantees that the function will just be looking
> at the value of the string, and won't modify it.)  You could go through
> and change all of the c/c++ client code to use const chars as
> arguments.  It would probably require a lot of work; in order to
> preserve the const qualifier in libplayerc you'd have to change the
> player_*prop_req_t structs (in libplayerinterface/player.h) so the
> property string is a const, then you'd have to change all the c and c++
> function prototypes and definitions, etc.

I started on that and then ended up at the stage of the player_*prop_req_t 
structs, at which point I stopped, waiting for some input from you guys.

> 
> As a workaround, you might also be able to do something like:
> 
> char* property = "crabbing";
> pp->SetIntProp(property,1);
> 
> This should get gcc off your back since you'd be passing a plain old
> char* like it wants.

Would probably work, but consts are nice in c++ and allow the compiler to 
optimise things so changing for consts where possible would be nice.

I'll look into it a bit more.

Fred

> 
> Rich
> 
> -----Original Message-----
> From: Fred Labrosse [mailto:[email protected]]
> Sent: Thursday, August 05, 2010 11:51 AM
> To: [email protected]
> Subject: [Playerstage-developers] const char *
> 
> All,
> 
> Whenever I call:
> 
> pp->SetIntProp("crabbing", 1);
> 
> my compiler complains:
> 
> warning: deprecated conversion from string constant to 'char*'
> 
> So I started editing clientproxy.h and clientproxy.cc in my svn working
> copy
> 
> to add the const's with a view of submitting a patch.
> 
> Obviously, the compilation fails because the underlying c code (in
> playerc.h)
> does not have the const's.  I haven't done any pure c in a while so I'm
> not too sure what to do with that.  I think gcc will be happy with
> added "const"s
> but this might not be generic enough.  And I'm not too sure what the
> repercussions of that will be with the rest of the code.  I could
> const_cast,
> but this somehow defeats the point...
> 
> Any suggestions?
> 
> Cheers,
> 
> Fred
> 
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