Double returns in C

开发者_Go百科

Is it possible to return two variables in C?

I would like to return a pointer as well as a string so that I can use both outside of the function.

Is this done with an array? if so, what type of array would it be? Void?

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No, you can only return one object. You can, however, return a struct type object and you can put your "multiple returns" into the struct:

typedef struct return_type
{
    void* pointer_; // You should, of course, use whatever the appropriate types
    char* string_;  // are for the objects that you are trying to return.
};

return_type f();

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You have two options:

1) Create a struct and return that

2) As parameters use pointers to what you want to change

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You could do something like this,

void func(void **pVoid, char **szString)
{
    pVoid = 0x1234;
    szString = "Hello";
}

void* pVoid;
char* szString;
func(&pVoid, &szString);

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you can return one item from the function then take a pointer as an argument that you will change. If you are given a char* (to return a string) and you change the location it points to (don't forget to free if it's already allocated!) then the caller should see a changed value on the other end of the pointer as well. You can return a pointer as the main return value of the function.