QMainWIndow not popping up when I run

[duma]

I have created a program which builds and runs without errors but no window pops up when I run. Can someone please tell me why.
My main function is below:

int main(int argc, char *argv[])
 {
         struct option long_option[] =
         {
                 {"help", 0, NULL, 'h'},
                 {"device", 1, NULL, 'D'},
                 {"rate", 1, NULL, 'r'},
                 {"channels", 1, NULL, 'c'},
                 {"frequency", 1, NULL, 'f'},
                 {"buffer", 1, NULL, 'b'},
                 {"period", 1, NULL, 'p'},
                 {"method", 1, NULL, 'm'},
                 {"format", 1, NULL, 'o'},
                 {"verbose", 1, NULL, 'v'},
                 {"noresample", 1, NULL, 'n'},
                 {"pevent", 1, NULL, 'e'},
                 {NULL, 0, NULL, 0},
         };
 
         int err;
         snd_pcm_hw_params_t *hwparams;
         snd_pcm_sw_params_t *swparams;
         int method = 0;
         snd_pcm_t *handle;
         snd_pcm_channel_area_t *areas;
         signed short *samples;
         unsigned int chn;
 
         snd_pcm_hw_params_alloca(&hwparams);
         snd_pcm_sw_params_alloca(&swparams);
 
                err = snd_output_stdio_attach(&output, stdout, 0);
         if (err < 0) {
                 printf("Output failed: %s\n", snd_strerror(err));
                 return 0;
         }
 
   /*      cout<<"Playback device is %s  "<<","<< device);
         cout<<"Stream parameters are %iHz, %s, %i channels  "<<","<< rate<<","<< snd_pcm_format_name(format), channels;
        cout<<"Sine wave rate is %.4fHz  "<<","<< freq;
         cout<<"Using transfer method: %s  "<<","<< transfer_methods[method].name;
 */
         if ((err = snd_pcm_open(&handle, device, SND_PCM_STREAM_PLAYBACK, 0)) < 0) {
                 printf("Playback open error: %s\n", snd_strerror(err));
                 return 0;
         }
 
         if ((err = set_hwparams(handle, hwparams, transfer_methods[method].access)) < 0) {
                 printf("Setting of hwparams failed: %s\n", snd_strerror(err));
                 exit(EXIT_FAILURE);
         }
         if ((err = set_swparams(handle, swparams)) < 0) {
                 printf("Setting of swparams failed: %s\n", snd_strerror(err));
                 exit(EXIT_FAILURE);
         }
 
         if (verbose > 0)
                 snd_pcm_dump(handle, output);
 
         samples = new signed short[(period_size * channels * snd_pcm_format_physical_width(format))];
 
 
 
         if (samples == NULL) {
                 printf("Not enough memory\n");
                 exit(EXIT_FAILURE);
         }
 
         areas = new snd_pcm_channel_area_t [channels];
 
         if (areas == NULL) {
                 printf("Not enough memory\n");
                 exit(EXIT_FAILURE);
         }
         for (chn = 0; chn < channels; chn++) {
                 areas[chn].addr = samples;
                 areas[chn].first = chn * snd_pcm_format_physical_width(format);
                 areas[chn].step = channels * snd_pcm_format_physical_width(format);
         }
 
 
         err = transfer_methods[method].transfer_loop(handle, samples, areas);
         if (err < 0)
                 printf("Transfer failed: %s\n", snd_strerror(err));
 
         delete [] areas;
         delete [] samples;
         snd_pcm_close(handle);
 
 
 
 
 
QApplication a(argc, argv);
wave w;
w.setWindowTitle("ESG Wave Creator");
 
 
w.show();
 
    return a.exec();
 
 
}

int main(int argc, char *argv[])
 {
         struct option long_option[] =
         {
                 {"help", 0, NULL, 'h'},
                 {"device", 1, NULL, 'D'},
                 {"rate", 1, NULL, 'r'},
                 {"channels", 1, NULL, 'c'},
                 {"frequency", 1, NULL, 'f'},
                 {"buffer", 1, NULL, 'b'},
                 {"period", 1, NULL, 'p'},
                 {"method", 1, NULL, 'm'},
                 {"format", 1, NULL, 'o'},
                 {"verbose", 1, NULL, 'v'},
                 {"noresample", 1, NULL, 'n'},
                 {"pevent", 1, NULL, 'e'},
                 {NULL, 0, NULL, 0},
         };

         int err;
         snd_pcm_hw_params_t *hwparams;
         snd_pcm_sw_params_t *swparams;
         int method = 0;
         snd_pcm_t *handle;
         snd_pcm_channel_area_t *areas;
         signed short *samples;
         unsigned int chn;

         snd_pcm_hw_params_alloca(&hwparams);
         snd_pcm_sw_params_alloca(&swparams);

                err = snd_output_stdio_attach(&output, stdout, 0);
         if (err < 0) {
                 printf("Output failed: %s\n", snd_strerror(err));
                 return 0;
         }

   /*      cout<<"Playback device is %s  "<<","<< device);
         cout<<"Stream parameters are %iHz, %s, %i channels  "<<","<< rate<<","<< snd_pcm_format_name(format), channels;
        cout<<"Sine wave rate is %.4fHz  "<<","<< freq;
         cout<<"Using transfer method: %s  "<<","<< transfer_methods[method].name;
 */
         if ((err = snd_pcm_open(&handle, device, SND_PCM_STREAM_PLAYBACK, 0)) < 0) {
                 printf("Playback open error: %s\n", snd_strerror(err));
                 return 0;
         }

         if ((err = set_hwparams(handle, hwparams, transfer_methods[method].access)) < 0) {
                 printf("Setting of hwparams failed: %s\n", snd_strerror(err));
                 exit(EXIT_FAILURE);
         }
         if ((err = set_swparams(handle, swparams)) < 0) {
                 printf("Setting of swparams failed: %s\n", snd_strerror(err));
                 exit(EXIT_FAILURE);
         }

         if (verbose > 0)
                 snd_pcm_dump(handle, output);

         samples = new signed short[(period_size * channels * snd_pcm_format_physical_width(format))];



         if (samples == NULL) {
                 printf("Not enough memory\n");
                 exit(EXIT_FAILURE);
         }

         areas = new snd_pcm_channel_area_t [channels];

         if (areas == NULL) {
                 printf("Not enough memory\n");
                 exit(EXIT_FAILURE);
         }
         for (chn = 0; chn < channels; chn++) {
                 areas[chn].addr = samples;
                 areas[chn].first = chn * snd_pcm_format_physical_width(format);
                 areas[chn].step = channels * snd_pcm_format_physical_width(format);
         }


         err = transfer_methods[method].transfer_loop(handle, samples, areas);
         if (err < 0)
                 printf("Transfer failed: %s\n", snd_strerror(err));

         delete [] areas;
         delete [] samples;
         snd_pcm_close(handle);





QApplication a(argc, argv);
wave w;
w.setWindowTitle("ESG Wave Creator");


w.show();

    return a.exec();


}

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[mvuori]

I can't see any windows getting created... unless your own type "wave" is such, but there is no way for anyone to know. If it is a subclassed QMainWindow, most likely its constructor has some kind of a problem.

[duma]

I can't see any windows getting created... unless your own type "wave" is such, but there is no way for anyone to know. If it is a subclassed QMainWindow, most likely its constructor has some kind of a problem.

There is a window being created at the bottom of my int main():

QApplication a(argc, argv);
wave w;
w.setWindowTitle("ESG Wave Creator"); 
 
w.show();
 
return a.exec();

QApplication a(argc, argv);
wave w;
w.setWindowTitle("ESG Wave Creator"); 
 
w.show();
 
return a.exec();

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Also, sorry for the lack of information. I used the designer to create the window widget wave.ui. The code above was the main in my main.cpp. wave.cpp and wave.h are below.

wave.cpp:

#include <QtGui>
#include <QApplication>
#include <qlineedit.h>
#include "ui_wave.h"
#include <QString>
#include <QObject>
#include <QDebug>
#include <stdio.h>
#include <cstdio>
#include <stdlib.h>
#include <cstdlib>
#include <string.h>
#include <cstring>
#include <sched.h>
#include <errno.h>
#include <getopt.h>
#include <alsa/asoundlib.h>
#include <sys/time.h>
#include <sstream>
#include <string>
#include <math.h>
#include <cmath>
#include <iostream>
#include "generate_sine.h"
#include "wave.h"
 
using namespace std;
 
 
static const char *device = "plughw:0,0";              // playback device
static snd_pcm_format_t format = SND_PCM_FORMAT_S16;    // sample format- change to 24-bit
static unsigned int rate = 96000;                       // stream rate
static unsigned int channels = 128;                     // count of channels
static unsigned int buffer_time = 500000;               // ring buffer length in us
static unsigned int period_time = 100000;               // period time in us
static double freq;                                     // sinusoidal wave frequency in Hz
static int verbose = 0;                                 // verbose flag
static int resample = 1;                                // enable alsa-lib resampling
static int period_event = 0; 				// produce poll event after each period
static snd_pcm_sframes_t buffer_size;
static snd_pcm_sframes_t period_size;
static snd_output_t *output = NULL;
static double ampl;
static double amplitude;
static bool isTrue = true;
 
 
wave::wave(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::wave)
{
    ui->setupUi(this);
 
 
   /* parent->
    generate_sine(const snd_pcm_channel_area_t *areas,
            snd_pcm_uframes_t offset,
            int count, double *_phase );*/
 
 
 
}
wave::~wave()
{
    delete ui;
}
 
 
 
void wave::on_pushButton_clicked()
{
        freq = ui->frequency->text().toDouble();
        ampl = ui->amplitude->text().toDouble();
        snd_pcm_t *handle;
        signed short *samples;
        snd_pcm_channel_area_t *areas;
        double phase = 0;
        signed short *ptr;
        int err, cptr;
 
                 while (1) {
 
 
                     generate_sine(areas, 0, period_size, &phase);
                         ptr = samples;
                         cptr = period_size;
                         while (cptr > 0) {
                                 err = snd_pcm_writei(handle, ptr, cptr);
                                 if (err == -EAGAIN)
                                         continue;
                                 if (err < 0) {
                                         if (xrun_recovery(handle, err) < 0) {
                                                 printf("Write error: %s\n", snd_strerror(err));
                                                 exit(EXIT_FAILURE);
                                         }
                                         break;  /* skip one period */
                                 }
                                 ptr += err * channels;
                                 cptr -= err;
                         }
                 }
         }
 
 
 
void wave::on_pushButton_2_clicked()
{
  isTrue = false;
 
}

#include <QtGui>
#include <QApplication>
#include <qlineedit.h>
#include "ui_wave.h"
#include <QString>
#include <QObject>
#include <QDebug>
#include <stdio.h>
#include <cstdio>
#include <stdlib.h>
#include <cstdlib>
#include <string.h>
#include <cstring>
#include <sched.h>
#include <errno.h>
#include <getopt.h>
#include <alsa/asoundlib.h>
#include <sys/time.h>
#include <sstream>
#include <string>
#include <math.h>
#include <cmath>
#include <iostream>
#include "generate_sine.h"
#include "wave.h"

using namespace std;


static const char *device = "plughw:0,0";              // playback device
static snd_pcm_format_t format = SND_PCM_FORMAT_S16;    // sample format- change to 24-bit
static unsigned int rate = 96000;                       // stream rate
static unsigned int channels = 128;                     // count of channels
static unsigned int buffer_time = 500000;               // ring buffer length in us
static unsigned int period_time = 100000;               // period time in us
static double freq;                                     // sinusoidal wave frequency in Hz
static int verbose = 0;                                 // verbose flag
static int resample = 1;                                // enable alsa-lib resampling
static int period_event = 0; 				// produce poll event after each period
static snd_pcm_sframes_t buffer_size;
static snd_pcm_sframes_t period_size;
static snd_output_t *output = NULL;
static double ampl;
static double amplitude;
static bool isTrue = true;


wave::wave(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::wave)
{
    ui->setupUi(this);


   /* parent->
    generate_sine(const snd_pcm_channel_area_t *areas,
            snd_pcm_uframes_t offset,
            int count, double *_phase );*/



}
wave::~wave()
{
    delete ui;
}



void wave::on_pushButton_clicked()
{
        freq = ui->frequency->text().toDouble();
        ampl = ui->amplitude->text().toDouble();
        snd_pcm_t *handle;
        signed short *samples;
        snd_pcm_channel_area_t *areas;
        double phase = 0;
        signed short *ptr;
        int err, cptr;

                 while (1) {


                     generate_sine(areas, 0, period_size, &phase);
                         ptr = samples;
                         cptr = period_size;
                         while (cptr > 0) {
                                 err = snd_pcm_writei(handle, ptr, cptr);
                                 if (err == -EAGAIN)
                                         continue;
                                 if (err < 0) {
                                         if (xrun_recovery(handle, err) < 0) {
                                                 printf("Write error: %s\n", snd_strerror(err));
                                                 exit(EXIT_FAILURE);
                                         }
                                         break;  /* skip one period */
                                 }
                                 ptr += err * channels;
                                 cptr -= err;
                         }
                 }
         }



void wave::on_pushButton_2_clicked()
{
  isTrue = false;

}

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wave.h:

#ifndef WAVE_H
#define WAVE_H
#include "ui_wave.h"
#include <alsa/asoundlib.h>
#include <QMainWindow>
#include <QObject>
#include "generate_sine.h"
#include "xrun_recovery.h"
 
namespace Ui {
    class wave;
}
 
class wave : public QMainWindow
{
    Q_OBJECT
 
public:
    explicit wave(QWidget *parent = 0);
    ~wave();
 
 
private slots:
    void on_pushButton_clicked();
 
    void on_pushButton_2_clicked();
private:
    Ui::wave *ui;
 
 
 
 
};
 
 
 
#endif // WAVE_H

#ifndef WAVE_H
#define WAVE_H
#include "ui_wave.h"
#include <alsa/asoundlib.h>
#include <QMainWindow>
#include <QObject>
#include "generate_sine.h"
#include "xrun_recovery.h"

namespace Ui {
    class wave;
}

class wave : public QMainWindow
{
    Q_OBJECT

public:
    explicit wave(QWidget *parent = 0);
    ~wave();


private slots:
    void on_pushButton_clicked();

    void on_pushButton_2_clicked();
private:
    Ui::wave *ui;




};



#endif // WAVE_H

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[duma]

I can't see any windows getting created... unless your own type "wave" is such, but there is no way for anyone to know. If it is a subclassed QMainWindow, most likely its constructor has some kind of a problem.

I created a program in Qt Creator called "wave" which is a QMainWindow.
As for my problem, I placed the line

return a.exec;

return a.exec;

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which is the line that executes the application and pops up the window. I placed this line at different parts of the code under in main() to see what line was stopping it from popping up. The window popped up when I placed it in all parts of the code starting from the top, but it stopped at the line:

err = transfer_methods[method].transfer_loop(handle, samples, areas);
if (err < 0)
printf("Transfer failed: %s\n", snd_strerror(err));

err = transfer_methods[method].transfer_loop(handle, samples, areas);
if (err < 0)
printf("Transfer failed: %s\n", snd_strerror(err));

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This is the line of code that stops my window from popping up. I don't know why. Any help would be greatly appreciated.

[jacks916]

I may be way off base, but aren't structs supposed to be declared outside of functions? in a global space?