[ERROR] msgget() "Function not implmented" Error : Cygwin

[Yeo Kai Wei via Cygwin]

Hi Cygwin,

May I ask if there will be an implementation of msgget() on Cygwin for 
Windows?

$ gcc -o sender sender.c

$ ./sender
key is 62720123
qid is -1
couldn't get queue id: Function not implemented

I googled the above error and it seems like this issue was raised in 2017.

It was meant to be fixed but I seem to have the same problem.

May I ask what I should do?

I've attached the files that I used.

Thank you.


Kind Regards,

YEO Kai Wei
#include <stdio.h>

#include <sys/ipc.h> //ftok(). File-to-key?

#include <sys/msg.h> //msgget

#include <stdlib.h>

#include <string.h>

#include "queue.h"

void report_and_exit(const char* msg)
{
        perror(msg);

        exit(-1);
}


int main()
{
        key_t key = ftok(PATHNAME, PROJECTID);

        if(key<0)
                report_and_exit("couldn't get key...");

        printf("key is %i\n", key);

        //msgget() creates message queue
        //Returns System V message qid associated with value of key argument.
        int qid = msgget(key, 0666 | IPC_CREAT);
        
        printf("qid is %i\n", qid);

        //Ran into error here
        if(qid<0)
                report_and_exit("couldn't get queue id");


        char* payloads[] = {"msg1","msg2","msg3","msg4","msg5","msg6"};

        int types[] = {1,1,2,2,3,3};

        int i;

        for( i = 0; i< MESSAGECOUNT ; i++)
        {
                //Type from queue.h
                queuedMessage msg;

                msg.type = types[i];

                strcpy(msg.payload, payloads[i]);

                msgsnd(qid,&msg,MESSAGELENGTH + 1, IPC_NOWAIT);

                printf("%s sent as type %i\n", msg.payload, (int) msg.type);
        }

        return 0;
}

#define PROJECTID 123

#define PATHNAME "queue.h"

#define MESSAGELENGTH 4

#define MESSAGECOUNT 6


typedef struct 
{
        long type;      //message type

        char payload[MESSAGELENGTH + 1]; //message. Some text.

} queuedMessage;


#include <stdio.h>

#include <sys/ipc.h> //ftok() convert pathname + ProjecID to System V IPC key

#include <sys/msg.h>

#include <stdlib.h>

#include "queue.h"

void report_and_exit(const char* msg)
{
        perror(msg);

        exit(-1);
}


int main()
{
        //Sys V IPC key
        key_t key = ftok(PATHNAME, PROJECTID);

        printf("key is %i\n", key);

        if(key<0)
                report_and_exit("key not gotten");

        //Create if needed, otherwise access. Not create again.
        int qid = msgget(key, 0666 | IPC_CREAT);

        if(qid < 0)
                report_and_exit("no access to queue...");

        //Different from sender.c
        int types[] = {3,1,2,1,3,2};

        int i;

        //Sender.c uses msgsend(). Receiver.c uses msgrcv()
        for(i=0; i < MESSAGECOUNT ; i++)
        {
                queuedMessage msg;

                if(msgrcv(qid,&msg, MESSAGELENGTH + 1, types[i], MSG_NOERROR | 
IPC_NOWAIT) < 0)
                        puts("msgrcv trouble...");

                printf("%s received as type %i\n", msg.payload, (int) msg.type);
        }       

        //Remove the q
        if(msgctl(qid, IPC_RMID, NULL) < 0)
                report_and_exit("trouble removing queue...");

        return 0;
}

-- 
Problem reports:      https://cygwin.com/problems.html
FAQ:                  https://cygwin.com/faq/
Documentation:        https://cygwin.com/docs.html
Unsubscribe info:     https://cygwin.com/ml/#unsubscribe-simple