How do I declare the buffer to reference on type x or y?

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void test(char * Buffer, int length)

{

struct x {

char a1;

int a2;

double d1;

};

struct y {

char a3;

int a4;

}

Buffer is parameter.
I want to declare this Buffer to depend on structure type x or y?
How do I do?

What I have tried:

During 2 hours I have code some programs to test it,
but failed.

Posted 15-Mar-16 7:55am

Member 12330615

Updated 15-Mar-16 11:08am

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jeron1 15-Mar-16 14:26pm

What do you mean 'depend on'?, maybe rephrase your question as it is unclear (at least to me).

Member 12330615 15-Mar-16 14:44pm

Sorry,
I want to the buffer to declare of the type of x or y.
Buffers are received from another server with many types, so I want to manage it according to the each type.

[no name] 15-Mar-16 15:17pm

A dirty solution: Pass the "type" of the buffer as extra Parameter (or at the beginning of the struct, maybe better) and according to the type make some "dirty cast".

3 solutions

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Richard MacCutchan · Answer 1 · 2016-03-15T11:08:00

Solution 3

You could use a union like:

C++

union foo
{
    struct x
    {
        char a1;
        int a2;
        double d1;
    };
    struct y
    {
        char a3;
        int a4;
    };
};

but that relies on you receiving some extra information that identifies which structure the data is in.

Posted 15-Mar-16 11:08am

Richard MacCutchan

Comments

Arthur V. Ratz 21-Mar-16 3:09am

Best answer using unions. +5.

OriginalGriff · Answer 2 · 2016-03-15T09:20:00

If you mean you need to have a x buffer handler and an y buffer handler for example, then you could either provide two overloaded methods, one for each type, or you could write a generic method if the actions taken were the same regardless of which type it was, and constrain the generic type to x and y.
Looking at your example structs, I think you need overloaded methods.

Patrice T · Answer 3 · 2016-03-15T11:04:00

Solution 2

What about the buffer having both types with a union ?
Unions[^]
Other data types - C++ Tutorials[^]
http://www.yolinux.com/TUTORIALS/LinuxTutorialC++Structures.html[^]

Posted 15-Mar-16 11:04am

Patrice T