Function not Declared in This Scope - error

[marinskye]

Hi folks, I'm relatively new to Qt programming and have come across an error stating that a function I had created was 'not declared in this scope'.
However, I don't see how this is the case as I included the header file in which it was declared into the offending file.

The error I get is:

' adcreader.cpp: In constructor ‘ADCreader::ADCreader()’:
adcreader.cpp:79:29: error: ‘gz_clock_ena’ was not declared in this scope
gz_clock_ena(GZ_CLK_5MHz,5);'

The file in which the error comes from is called 'adcreader.cpp' and I have included the relevant sections to the error below, any help would be greatly appreciated. I do apologise for the length of the post.

```cpp

1 #include "adcreader.h"
  2 #include <QDebug>
  3 
  4 #include "gpio-sysfs.h"
  5 #include <fcntl.h>
  6 #include <sys/ioctl.h>
  7 #include <linux/types.h>
  8 #include <linux/spi/spidev.h>
  9 #include <assert.h>
 10 #include "gz_clk.h"
 11 
 12 #define ARRAY_SIZE(a) (sizeof(a) / sizeof((a)[0]))
 13 
 14 #define MAX_SAMPLES 65536
 15 
 16 ADCreader::ADCreader()
 17 {
 18   int ret = 0;
    ...........................
 
 77   // enable master clock for the AD
 78   // divisor results in roughly 4.9MHz
 79   // this also inits the general purpose IO
 80   gz_clock_ena(GZ_CLK_5MHz,5);
 
.....
 
}

1 #include "adcreader.h"
  2 #include <QDebug>
  3 
  4 #include "gpio-sysfs.h"
  5 #include <fcntl.h>
  6 #include <sys/ioctl.h>
  7 #include <linux/types.h>
  8 #include <linux/spi/spidev.h>
  9 #include <assert.h>
 10 #include "gz_clk.h"
 11 
 12 #define ARRAY_SIZE(a) (sizeof(a) / sizeof((a)[0]))
 13 
 14 #define MAX_SAMPLES 65536
 15 
 16 ADCreader::ADCreader()
 17 {
 18   int ret = 0;
    ...........................

 77   // enable master clock for the AD
 78   // divisor results in roughly 4.9MHz
 79   // this also inits the general purpose IO
 80   gz_clock_ena(GZ_CLK_5MHz,5);
 
.....

}

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```

The file in which I declared the function is called gz_clk.h and I have included its code below:

```cpp

22 #ifndef GZ_CLK_H
 23 #define GZ_CLK_H
 24 #include <QtCore> 
 25 #include<bcm2835.h>
 26 
 27 #define GZ_CLK_5MHz 0 
 28 #define GZ_CLK_125MHz 1
 29 
 30 //int gz_clock_ena(int speed, int divider);
 31 //int gz_clock_dis();
 32 
 33 //#endif // GZ_CLK_H
 34 
 35 class gz_clk : public QObject
 36 {
 37 
 38 Q_OBJECT
 39 
 40 public:
 41 gz_clk();
 42 int gz_clock_ena(int speed, int divider);
 43 int gz_clock_dis();
 44 
 45 
 46 };
 47 
 48 #endif // GZ_CLK_H

22 #ifndef GZ_CLK_H
 23 #define GZ_CLK_H
 24 #include <QtCore> 
 25 #include<bcm2835.h>
 26 
 27 #define GZ_CLK_5MHz 0 
 28 #define GZ_CLK_125MHz 1
 29 
 30 //int gz_clock_ena(int speed, int divider);
 31 //int gz_clock_dis();
 32 
 33 //#endif // GZ_CLK_H
 34 
 35 class gz_clk : public QObject
 36 {
 37 
 38 Q_OBJECT
 39 
 40 public:
 41 gz_clk();
 42 int gz_clock_ena(int speed, int divider);
 43 int gz_clock_dis();
 44 
 45 
 46 };
 47 
 48 #endif // GZ_CLK_H

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```

The file in which I implemented the function was in a file called gz_clk.cpp and its code is below:

```cpp

22 #include "gz_clk.h"
 23 #include <stdio.h>
 24 #include <stdlib.h>
 25 #include <unistd.h>
 26 #include <QtCore>
 27 
 28 #define GZ_CLK_BUSY (1 << 7)
 29 
 30 gz_clk::gz_clk()
 31 
 32 {
 33 }
 34 
 35 int gz_clk::gz_clock_ena(int speed, int divisor) {
 36   int speed_id = 6;
 37   if (speed < GZ_CLK_5MHz || speed > GZ_CLK_125MHz) {
 38     printf("gz_clock_ena: Unsupported clock speed selected.\n");
 39     printf("Supported speeds: GZ_CLK_5MHz (0) and GZ_CLK_125MHz (1).");
 40     exit(-1);
 41   }
 42   if (speed == 0) {
 43     speed_id = 1;
 44   }
 45   if (divisor < 2) {
 46     printf("gz_clock_ena: Minimum divisor value is 2.");
 47     exit(-1);
 48   }
 49   if (divisor > 0xfff) {
 50     printf("gz_clock_ena: Maximum divisor value is %d.", 0xfff);
 51     exit(-1);
 52   }
 53   if (bcm2835_init() !=1) {
 54     printf("gz_clock_ena: Failed to initialize I/O\n");
 55     exit(-1);
 56   }
 57   usleep(5);
 58   bcm2835_gpio_fsel(RPI_GPIO_P1_07, BCM2835_GPIO_FSEL_ALT0);
 59   *(bcm2835_clk + 0x1C) = 0x5A000000 | speed_id;    // GPCLK0 off
 60   while (*(bcm2835_clk + 0x1C) & GZ_CLK_BUSY) {}    // Wait for BUSY low
 61   *(bcm2835_clk + 0x1D) = 0x5A002000 | (divisor << 12); // set DIVI
 62   *(bcm2835_clk + 0x1C) = 0x5A000010 | speed_id;    // GPCLK0 on
 63   return 0;
 64 
 65 }
 66 
 67 int gz_clk::gz_clock_dis() {
 68   if (bcm2835_init() !=1) {
 69     printf("gz_clock_dis: Failed to initialize I/O\n");
 70     exit(-1);
 71   }
 72   bcm2835_gpio_fsel(RPI_GPIO_P1_07, BCM2835_GPIO_FSEL_INPT);
 73   return 0;
 74 }

22 #include "gz_clk.h"
 23 #include <stdio.h>
 24 #include <stdlib.h>
 25 #include <unistd.h>
 26 #include <QtCore>
 27 
 28 #define GZ_CLK_BUSY (1 << 7)
 29 
 30 gz_clk::gz_clk()
 31 
 32 {
 33 }
 34 
 35 int gz_clk::gz_clock_ena(int speed, int divisor) {
 36   int speed_id = 6;
 37   if (speed < GZ_CLK_5MHz || speed > GZ_CLK_125MHz) {
 38     printf("gz_clock_ena: Unsupported clock speed selected.\n");
 39     printf("Supported speeds: GZ_CLK_5MHz (0) and GZ_CLK_125MHz (1).");
 40     exit(-1);
 41   }
 42   if (speed == 0) {
 43     speed_id = 1;
 44   }
 45   if (divisor < 2) {
 46     printf("gz_clock_ena: Minimum divisor value is 2.");
 47     exit(-1);
 48   }
 49   if (divisor > 0xfff) {
 50     printf("gz_clock_ena: Maximum divisor value is %d.", 0xfff);
 51     exit(-1);
 52   }
 53   if (bcm2835_init() !=1) {
 54     printf("gz_clock_ena: Failed to initialize I/O\n");
 55     exit(-1);
 56   }
 57   usleep(5);
 58   bcm2835_gpio_fsel(RPI_GPIO_P1_07, BCM2835_GPIO_FSEL_ALT0);
 59   *(bcm2835_clk + 0x1C) = 0x5A000000 | speed_id;    // GPCLK0 off
 60   while (*(bcm2835_clk + 0x1C) & GZ_CLK_BUSY) {}    // Wait for BUSY low
 61   *(bcm2835_clk + 0x1D) = 0x5A002000 | (divisor << 12); // set DIVI
 62   *(bcm2835_clk + 0x1C) = 0x5A000010 | speed_id;    // GPCLK0 on
 63   return 0;
 64 
 65 }
 66 
 67 int gz_clk::gz_clock_dis() {
 68   if (bcm2835_init() !=1) {
 69     printf("gz_clock_dis: Failed to initialize I/O\n");
 70     exit(-1);
 71   }
 72   bcm2835_gpio_fsel(RPI_GPIO_P1_07, BCM2835_GPIO_FSEL_INPT);
 73   return 0;
 74 }

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```

[Prady_80]

Hi,

You have not invoked the function with the gz_clock_ena(...) with an object of class gz_clk. You can only use the function directly if you have inherited ADCreader from gz_clk. This has nothing to do with Qt.
Just a suggestion, please read the posting norms and use code formatting while posting.

[marinskye]

Hi,

You have not invoked the function with the gz_clock_ena(...) with an object of class gz_clk. You can only use the function directly if you have inherited ADCreader from gz_clk. This has nothing to do with Qt.
Just a suggestion, please read the posting norms and use code formatting while posting.

Hi, thanks a lot for your suggestion - a bad mistake. However, before checking here I managed to find another solution to my problem. The problem seemed to be a linking problem rather than a compiling one. Despite being installed, the library 'bcm2835' was not being properly detected. In the project's '.pro' file, I added the line 'LIBS += -lbcm2835 -lrt' - which allowed the program to compile and link without error.

[marinskye]

Good solution!