Programming

Hi
We are using a code generator for initializing structures with the #define macro. Compiling it with the GCC 2.8.1 (with -ansi) it OK. But when we are using the SUN C 5.0 compiler it screams.

Following is a code sample:


#include <stdlib.h>
#include <stdio.h>

typedef struct TEST3 {
int E;
int F;
} TEST3;

typedef struct TEST2 {
int C;
TEST3 D;
} TEST2;

typedef struct TEST {
int A;
TEST2 B;
} TEST;

#define TEST3_NS_C (TEST3) {\
6,\
8}
#define TEST2_NS_C (TEST2) {\
2,\
TEST3_NS_C}
#define TEST_NS_C (TEST) {\
1,\
TEST2_NS_C}

main(int argc, char *argv[])
{

TEST T ; /*= TEST_NS_C;*/
T = TEST_NS_C;
printf("%d %d %d %d", T.A, T.B.C, T.B.D.E, T.B.D.F);
exit(1);

}



Does anybody knows why that happens since SUN C5.0 is ANSI/ISO compliant ?

Thanx

Can you post the error messages?

From the gcc man page... Try "gcc -ansi -pedantic".

I have tried your code on gcc without either -ansi or -pendantic. I can't get it to compile with any compiler no matter what I do. We do have an older version of gcc, "gcc --version" says 2.95.3. But visually inspecting the code, I'm not surprised that it doesn't compile. Did the code get garbled as you included it the post?

OK,
we used the -pedantic and the gcc (ver 2.8.1) complained at line
T = TEST_NS_C; with the following errors
test.c: In function `main':
test.c:33: warning: ANSI C forbids constructor expressions
test.c:33: warning: ANSI C forbids constructor expressions
test.c:33: warning: ANSI C forbids constructor expressions

So from what -ansi option it's not a safe way anymore.

The error we get in Sun C5.0 compiler is in the same line and it reads
test.c line 33: syntax error before or at: {
which I beleve is for the same reason.

And here is the million dollar question.

How can we initialize complex structures like in the example?
Our application has to send large amount of different messages through TCP or UPD interfaces and we have prepared a code generator that would intialize all the message values to NO_STATEMENT (what ever that means).

Thanx once more for the help.

Andonis

I think that I now mostly understand the code that you posted. You're right about gcc. I suggest that you do most of your testing with a C compiler. There is a lot of code out there that happily states "gcc required", a situation simliar to those "IE required" web pages.

You are doing a lot of "typedef struct X { } X". That makes X both a typedef and name of a stucture. Unless you have a very good reason for that, just use "typedef struct { } X".

When you do "#define X_NS_C (X) {...}", what function is the (X) supposed to serve? That is the one part that I can't figure out. I finally just assumed it was a comment and dropped it.

You need a \n in your printf. I never could get my version of gcc to compile your program. When you run your program after a gcc compile, do you get a trailing \n somehow?

The exit(1) is interesting, but I couldn't resist the urge to switch it to exit(0).

Code:

#include <stdlib.h> 
#include <stdio.h> 

typedef struct { 
        int E; 
        int F; 
        } TEST3; 

typedef struct { 
        int C; 
        TEST3 D; 
        } TEST2; 

typedef struct { 
        int A; 
        TEST2 B; 
        } TEST; 

#define TEST_NS_C  { 1, TEST2_NS_C } 
#define TEST2_NS_C { 2, TEST3_NS_C } 
#define TEST3_NS_C { 6, 8 } 

main(int argc, char *argv[]) 
{ 
        TEST T = TEST_NS_C;
        printf("%d %d %d %d \n", T.A, T.B.C, T.B.D.E, T.B.D.F); 
        exit(0); 
}

Of course, in real life, I would lose those #defines and just go with:
TEST T = { 1, { 2, { 6, 8 } } };
but I guess that you need those defines for some reason. Do you really need to split them to several lines? Even machine generated C code should be readable.

I have tried my code on several c compilers. HP's c++ compiler issued a warning because main() is not typed, but the resulting program ran fine. Other than that, it compiled fine everywhere, including with gcc.

You lost me with that NO_STATEMENT stuff...I hope that wasn't too important.