From: Arne Vajhøj [arne@vajhoej.dk]
Sent: Tuesday, April 15, 2003 9:16 AM
To: Info-VAX@Mvb.Saic.Com
Subject: Re: Communication Problem between process and subprocess via
mailbox

SUBPROC.H
---------

void sub_init();
void sub_put(char *line);
void sub_wait(int n);
int sub_get(char *line,long nb);
void sub_end();

SUBPROC.C
---------

#include <stdlib.h>
#include <string.h>
#include <descrip.h>
#include <clidef.h>
#include <ssdef.h>
#include <iodef.h>

short chani,chano;
#define maxlinlen 256
char *bigbuf[10000];
int wptr = -1;
int rptr = -1;

long sys$crembx();
long lib$spawn();
long sys$qiow();
long lib$wait(float *t);

int sub_help_get(char *line,long nb)
{
    short read = IO$_READVBLK | IO$M_NOW;
    short iosb[4];
    if (sys$qiow(0,chano,read,iosb,0,0,line,nb,0,0,0,0)==SS$_NORMAL) {
       if (iosb[0]==SS$_NORMAL) {
          line[iosb[1]] = '\0';
          return 1;
       } else {
          return 0;
       }
    } else {
       return 0;
    }
}

void sub_set_ast();

void sub_ast()
{
    do {
       wptr++;
       bigbuf[wptr] = malloc(maxlinlen+1);
    } while (sub_help_get(bigbuf[wptr],maxlinlen));
    wptr--;
    sub_set_ast();
    return;
}

void sub_set_ast()
{
    short setatt = IO$_SETMODE | IO$M_WRTATTN;
    sys$qiow(0,chano,setatt,0,0,0,sub_ast,0,0,0,0,0);
    return;
}

void sub_init()
{
    long messiz = 256;
    long bufsiz = 4096;
    long flags = CLI$M_NOWAIT;
    $DESCRIPTOR(inpdes,"SUB_INPUT_MBX");
    $DESCRIPTOR(outpdes,"SUB_OUTPUT_MBX");
    sys$crembx(0,&chani,messiz,bufsiz,0,0,&inpdes);
    sys$crembx(0,&chano,messiz,bufsiz,0,0,&outpdes);
    sub_set_ast();
    lib$spawn(0,&inpdes,&outpdes,&flags,0,0,0,0,0,0,0,0,0,0);
    return;
}

void sub_put(char *line)
{
    short write = IO$_WRITEVBLK | IO$M_NOW;
    sys$qiow(0,chani,write,0,0,0,line,strlen(line),0,0,0,0);
    return;
}

void sub_wait(int n)
{
    float t;
    t = n;
    lib$wait(&t);
    return;
}

int sub_get(char *line,long nb)
{
    if (rptr<wptr) {
       rptr++;
       strncpy(line,bigbuf[rptr],nb-1);
       line[nb-1] = '\0';
       return 1;
    } else {
       return 0;
    }
}

void sub_end()
{
    long fnd,bool;
    char line[81];
    sub_put("LOGOUT/BRIEF");
    bool=1;
    while(bool) {
       sub_wait(1);
       fnd = sub_get(line,sizeof(line)-1);
       if (!fnd) bool=0;
    }
    return;
}