different ways of typedefing

[dayalsoap]

In this project I'm working on, they do this:

struct aggregator_t
{
	.... bunch of ints
};

typedef struct aggregator_t aggregator;

aggregator *ags;

Is this different than doing

typedef struct aggregator_t
{
 .......
} aggregator, *ags;

If it's different, is there any prefered way?

[CommonTater]

The result is the same.

If you are going to get into windows programming, they have settled on

typedef struct tagSTRUCTNAME
  {
     ... bunch of vars
   } STRUCTNAME, *PSTRUCTNAME;

It pretty much all amounts to the same thing and your own style will likely evolve according to where you do most of your work... I do mostly windows api coding, so I prefer the windows way. Your mileage may vary

[orientuser]

They are different.
In the 1st code, a structure variable named args is declared and then args is an object. In the 2nd code, however, args is a new alias for the type "struct aggregator_t *" .

[dayalsoap]

They are different.
In the 1st code, a structure variable named args is declared and then args is an object. In the 2nd code, however, args is a new alias for the type "struct aggregator_t *" .

I think the other guy is correct. I think args is a pointer in both cases

[laserlight]

I think the other guy is correct. I think args is a pointer in both cases

Well, this is a case where one can construct a program to help determine the answer. For example:

typedef struct aggregator_t
{
    int n;
} aggregator, *ags;

int main()
{
    struct aggregator_t x;
    ags p = &x;
    return 0;
}

Now, if ags is an alias for struct aggregator_t* as orientuser stated, the above program should compile. On the other hand, if CommonTater is right, it should not compile, because one cannot use a variable name as a type name. So, what do you think is the answer now?

[stahta01]

@laserlight:

I was not sure what would happen; your code example was enlightening.

@CommonTater: You might want to re-think your answer that they are the same.

Tim S.

[CommonTater]

@laserlight:

I was not sure what would happen; your code example was enlightening.

@CommonTater: You might want to re-think your answer that they are the same.

Tim S.

I did not say they were the same...

"It pretty much all amounts to the same thing"

That is to say you end up with a struct and a pointer to the struct....

[laserlight]

I did not say they were the same...

"It pretty much all amounts to the same thing"

That is to say you end up with a struct and a pointer to the struct....

Very well, it looks like I have to take a direct approach: you're wrong. In this code snippet, aggregator is an alias for struct aggregator_t, and ags is a pointer to a struct of that type:

struct aggregator_t
{
    int n;
    int m;
};

typedef struct aggregator_t aggregator;

aggregator *ags;

But in this code snippet, aggregator is an alias for struct aggregator_t, and ags is an alias for struct aggregator_t*:

typedef struct aggregator_t
{
    int n;
    int m;
} aggregator, *ags;

Since ags in the former is not the same as ags in the latter, the code snippets do not amount to the same thing.

[orientuser]

They are different.
In the 1st code, a structure variable named args is declared and then args is an object. In the 2nd code, however, args is a new alias for the type "struct aggregator_t *" .

sorry, i made a mistake. In the 1st code snippet, args is a pointer to struct aggregator_t, not a structure variable.