[aspectc-user] Problems with weaving C program

Mikael Björk mikbj303 at student.liu.se
Wed Apr 21 11:52:47 CEST 2004


I'm working on a real-time embedded database system called COMET. In this project we are using aspectC++ to add functionality to the database.

Since it is an embedded system we are using C, but while there is no AspectC weaver, we use the AspectC++ weaver. Unfortunately this causes some difficulties.

In some instances we put all the arguments to a function into a struct. That way it is easy to add new arguments with aspects. A problem arises when we want to transfer the values of the introduced arguments on to another struct for another function call within the first function. I illustrate with a brief example:

struct structA
   int x;

struct structB
   int x;

int functionA(structA a)
   structB b;
   b.x = a.x;
   return functionB(b);

If we for example extend structA and structB with "int y", we would like to weave "b.y = a.y" into the code before the call to functionB, so that our weaved changes to functionB can use the variable y.

As far as I have understood it after some experimentation, I believe that it is not possible to access the arguments of functionA in an advice which happens "before" functionB is "called".

Am I wrong? And if not, is there some nice way around this problem?

Mikael Björk

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