CODEWITHSUNDEEP
cpthreads
Pyro
Pyro

Reputation: 17

Returning value from a Pthread

I have a function shown below which I pass it to pthread_create. I have read plenty of posts and implemented them on my code, However I still can not return a value.

void *threaded_FFT(void* arg) {
    struct arg_struct *data = (struct arg_struct *)arg;

    data->base = data->fft->in;

    for(i=0;i<N;i++){
        data->base[i].re =  data->input[i]; data->base[i].im =0.0; 
    }

    usleep(1);

    gpu_fft_execute(data->fft);
    data->base = data->fft->out;

    for(i=0;i<N;i++){
        data->output[i]= sqrt(((data->base[i].re)*(data->base[i].re))+((data->base[i].im)*(data->base[i].im))); 
    }

    return (void *)data->output; 
}

When I add a printf line to display data->output[0...N], I can clearly see that they've proper values which shows function working properly.

I'm trying this in my main function

void *outData;
...
pthread_join(threads[],&outData);
...
printf("%f\n",(float *)outData);

This always returns me value of 0.000000

Upvotes: 0

Views: 1882

Answers (1)

Florian Weimer
Florian Weimer

Reputation: 33719

printf("%f\n",(float *)outData);

%f expects a floating point value, not a pointer. This might work:

printf("%f\n", ((float *)outData)[0]);

You have not posted your type definitions, so it is not clear whether outData actually points to a float value.

Upvotes: 2

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