Put together function name from type in macro

Hi!

I'm doing some experimentation with C and trying some stuff out.
Right now I am playing around with macros and I found the GCC typeof keyword which I found intriging.

Anyway so I am trying to make a "initializer" macro which will more or less take any type of structure and call it's "construct function"

More or less something like this:

Code:

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SomeType foo;
construct( foo ); // Becomes -> SomeType_Construct( &foo );

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Though I am having problem with pasting together the type and the _Construct and is wondering if anyone else know what to do or got a better idea?

Doing this doesn't work as it tries to construct this string: typeof( object )_Construct( &object )

Code:

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#define construct( object ) typeof( object )##_Construct( &object )

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If you got a better way you know to solve the same problem then of course I am interested in that as well.

O_o

That's not going to work.

The `typeof' thing is not a macro to be expanded; it is an operator (keyword) like `sizeof'.

The `typeof', like `sizeof', resolves during compilation proper and not the processing phase.

Soma

Rather than trying to fake constructors in C, I suggest you learn a little C++.

Probably best. I had a bit of a think about this, as the post by the OP would have been quite a nice and simple trick if it worked. I couldn't think of anything much though - nothing that hasn't been covered in various places.

Quote:

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Originally Posted by Groogy

Anyway so I am trying to make a "initializer" macro which will more or less take any type of structure and call it's "construct function"

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Yeah. C++. Definitely. Constructors. Automatically called when you create the struct. Failing that, you can do it your way with overloaded functions, define construct() functions with different types, but I wouldn't bother.

The last C standard defines a new construct to do exactly that, without compiler extension like typeof(), but it's only supported by clang and gcc (?) so far.

Code:

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#define construct(x) _Generic((x),\
    char: construct_char,\
    int: construct_int,\
    struct foo: construct_st_foo,\
    ...)(x)

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Google "c11 _Generic" for examples.