using WTO to print from with in Metal C

Question

I’m trying to use the WTO instruction from with in Metal C to print out "Hello World" to my job log. This is based on the example in section 1.2.3.5 of the z/OS V1R10.0 Metal C Programming Guide and Reference It appears when I use WTO I am having either issues with my buffer containing 0 or ASCII to EBCDIC conversion. I’ve pasted the relevant section of my job log below, followed by my code, then the code from the IBM example which I could not get to compile. Job log

09.01.56 J0686275  IEF403I IMIJWS0G - STARTED - TIME=09.01.56
 09.01.56 J0686275  +...0.......
 09.01.56 J0686275  -                                         --TIMINGS (MINS.)--            ----PAGING COUNTS---
09.01.56 J0686275  -IMIJWS0G          GO          00      6    .00    .00    .00   1292   0      0      0      0     0     1
 09.01.56 J0686275  IEF404I IMIJWS0G - ENDED - TIME=09.01.56

My code

#include 
#include 
#include 
 int main()
 {
                                    struct WTO_PARM {
               unsigned short len;
               unsigned short code;
               char* text;
            } wto_buff = { 4+11, 0, "hello world" };
            __asm( " WTO  MF=(E,(%0)) " : : "r"(&wto_buff));

        }

IBM code

int main() {

            struct WTO_PARM {
               unsigned short len;
               unsigned short code;
               char text[80];            } wto_buff = { 4+11, 0, "hello world" };            __asm( " WTO  MF=(E,(%0)) " : : "r"(&wto_buff));
            return 0;
        }

Answer 1

The IBM example worked for me (under Z/os 1.9) but I had to add a pragma to set the codepage: on top of the example: #pragma filetag("IBM-500") The compiler did not accept the [ and ] in the char text[80]; I've tried to change char text[80] into char *text as well but I got the same strange result as you.

Answer 2

Perhaps the layout in memory of the two versions of the struct isn't the same? I tried this in gcc:

#include <stdio.h>

struct WTO_PARM {
    unsigned short len;
    unsigned short code;
    char *text;
};

int main()
{
    struct WTO_PARM moo = { 4+11,0,"hello" };
    printf("size %zu struct %p string %p\n", sizeof(struct WTO_PARM),&moo,moo.text);
    return 0;
}

Here are the results:

size 8 struct 0x22cce0 string 0x402000

However, if I change the type of the text parameter to char[80], the results change to:

size 84 struct 0x22cc80 string 0x22cc84

The WTO instruction likely expects the string to be packed right into that struct.

Answer 3

Why can't you compile the IBM sample? It works fine for me - perhaps you could show us your compiler parms and error messages?

Answer 4

Do you edit your code via TN3270 client ? It's very likely that the problem is related to the code page in your emulator. For example I need to make the following change in ISPF : c x'4A' x'AD' all (for [ ) and c x'5A' x'BD' (for ]) in order to compile the source ...