problem with function declaration and definition mismatch using GCC

[阎淼 <yanmiaobest@xxxxxxxxx>]

Hi,

 I am using GCC 4.1.2 on a project, the prototype and definition of a
function is mismatch, but the programs

 compiles and works fine,   how GCC compiles following code and checks
the prototype ?

 in file a.h :

       typedef struct {...}  struct_b;

       extern  int  func_A ( struct_a * socket, struct_b * flash);

 in file a.c:

       #include "a.h"

       int func_A( struct_a * socket, struct_b vol)
       {
                 .....
                 vol.read = read;
                 vol.write = write;
                 .....
                 return 0;
       }

and another file b.c:

      #include "a.h"

      int func_B(.....)
      {
            struct_b flash;

            func_A( ...,   &flash);


            flash.read(xxx);
      }


GCC compiles this piece of code without warnings, and it works fine.
But there is a  mismatch between declaration and definition  of
func_A,

should there be a warning ?  I compiled the code with -ansi and -Wall
options.  And when I changed the prototype to

extern  int  func_A ( struct_a * socket, struct_b * vol),   GCC gives
a error saying conflicting types of func_A.



Best Regards!
Miao Yan