jjleto wrote:
Victor Bazarov a écrit :
jjleto wrote:
I have a C program that uses in some parts macros with # and ## like in:
#define GET_FUNC_DECL(name) char *get##name();
#define GET_FUNC_IMPL(name) char *get##name() { /* some stuff */;
return #name; }
Is there a way to achieve this without macros in C++ ? With templates
perhaps ?
It depends on what you mean by "this". Preprocessor macros are a way to
substitute one string in the source code with another while performing
some operations like converting to literals or merging tokens. It is all
done before the compiler gets to it. Templates are a way to make
compiler
generate code when needed based on arguments provided.
I understand that. But after preprocessing and compiling, we end with
code generated for the macros/templates (although completely
differentely I guess)
What exactly are you trying to accomplish?
V
I just try to get rid of the macros.
Why?
I was thinking of something like
template<char *name>
char *get()
{
/* ... */
return name;
}
and a call like
get< "foo" >();
But this does not compile.
And it won't. String literals have internal linkage, therefore they
cannot be used as template arguments. But that's not the actual issue
here, is it?
Again, what are you trying to accomplish? Why not, for example, have
the _function_ argument instead of the template argument:
char* get(const char* whattoget) {
if (isname(whattoget))
return name;
else if (issomethingelse(whattoget))
return somethingelse;
else
return NULL;
}
Yes, that's run-time behaviour, not compile-time.
"Getting rid of macros" should not be the goal to pursue. Macros are just
as part of the C++ language as templates, and they are not on their way
out, and won't be any time soon. If they help you organize the code and
make it easier to write and understand, why get rid of them?
Victor
.
