making 2 processes run simultaniously

[smegly]

Hi,

Is there a ay to get lineRead and testModule to run at the same time. I have kind of implemented the fork method. but since it goes into an if statement lineread is executed and completed before testModule has a chance to run. In what order, or if i'm on the wrong track, what method should i use to make these modules run in a multitasking environment!!

Matt

pid_t pid = fork();
        if ( pid == 0 ) 
        {
            lineRead(fptr2, fptr1);
        // stuff for child only
        // this normally exits the process when its done
        } 
        else if ( pid != -1 ) 
        {
            testModule();
  // stuff in parent, if child runs
        } else {
            testModule1();
  // stuff in parent, with no child
        }

[XSquared]

They will run simultaneously the way you have it, although they don't share the same memory space.

[smegly]

Maybe I see concurrently in a different perspective,

at present the lineRead executes and completes, before the testModule is implemented.

To help, the code for lineRead and testModule are included.

void lineRead(FILE *fin, FILE *fout)
{
    char buff[MAX_LEN];
    
    while (fgets(buff, MAX_LEN, fin) != NULL)
    {
       
       fputs(buff, fout);
       printf("%s and pidvalue is %d \n", buff, getpid());
       sleep(3);
    }
}

void testModule()
{
    int i = 0;
    for(i=0; i<10; i++)
    {
        printf("Hi");
        sleep(2);
    }
}

Matt

[Codeplug]

If you want to control the order in which things run, then you'll have to use some form of interprocess communication/synchronization.
Otherwise, the kernel decides who runs when and for how long.

The code never truly runs at the same time unless your running on a machine with more than 1 CPU.

gg

[Hammer]

Maybe you should explain what you're trying to achieve, so that we can advise you better. I see no direct relationship between lineRead() and testModule(), so what makes you think one should wait for the other?

[smegly]

I don't want one to wait for the other . .

I want them to work simultaniously.. testModule will eventually be the entire program, and lineRead will retrieve a customer from the customer file periodically at Ts time. Therefore it must run whilst the main program is working. It is kinda like a sub-program.

Matt

[chrismiceli]

Might want to then look into threads.