error: expected identifier before string constant

Vaclav_

I hope I can explain this problem. I can make an instance of a class in my main()

CLASS\_I2CIO   i2c\_ads1115(DEVICE\_I2C,ADDRESS\_ADS);

no problema. But if I add same code as class variable - I need an access to the class form main() - I get the following error.

class C_VNA {
public:
C_VNA();
virtual ~C_VNA();

C\_Utility utility;
CLASS\_LCM1602 i2c;	// default constructor x,x,x,x);
CIOCTLGPIO gpio;    // GPIo
C\_IOCTL\_SPI spi;    // temporary not coded
C\_DDS\_60 dds;       // frequency
C\_AD8302\_Detector det;
C\_ADS1115 ads;
CLASS\_I2CIO   i2c\_ioctl;       // genric i2c using ioctl

error here
CLASS_I2CIO i2c_ads1115_test(DEVICE_I2C,ADDRESS_ADS);
error here
};

Partial compiler output

Compiler executable checksum: 606522cdd68a1ba2fd9e2930e9d38d0d
In file included from ../src/MODULES/M_VNA/CVNA.cpp:8:0:
../src/MODULES/M_VNA/CVNA.h:28:20: error: expected identifier before string constant
#define DEVICE_I2C "dev/i2c-1"
^
../src/MODULES/M_VNA/CVNA.h:60:36: note: in expansion of macro ‘DEVICE_I2C’
src/MODULES/M_VNA/subdir.mk:18: recipe for target 'src/MODULES/M_VNA/CVNA.o' failed
CLASS_I2CIO i2c_ads1115_test(DEVICE_I2C,ADDRESS_ADS);
^
../src/MODULES/M_VNA/CVNA.h:28:20: error: expected ‘,’ or ‘...’ before string constant
#define DEVICE_I2C "dev/i2c-1"
^
../src/MODULES/M_VNA/CVNA.h:60:36: note: in expansion of macro ‘DEVICE_I2C’
CLASS_I2CIO i2c_ads1115_test(DEVICE_I2C,ADDRESS_ADS);
^
make: *** [src/MODULES/M_VNA/CVNA.o] Error 1

There is nothing special about #defines

// devices
#define DEVICE_SPI "dev/spidev0.0"
#define DEVICE_I2C "dev/i2c-1"

// define i2c addresses
#define ADDRESS_HITACHI 0x27
#define ADDRESS_ADS 0x48

The error "points " to #define which is redefined in this class - temporary for test purposes. I did look thru similar problems and they all indicate the #define is NOT the issue, however I am unable to figure this out and correct it. Any help would be appreciated. Cheers

Lost User

Where is the definition of CLASS_I2CIO and its constructors?

Vaclav_

Here is the part in question

class CLASS_I2CIO {
public:
CLASS_I2CIO();
CLASS_I2CIO(char Device, int Address);
CLASS_I2CIO(int width, int length, int height)
: m_width(width), m_length(length), m_height(height)
{}

CLASS\_I2CIO(char \*x1, int y1); // :

this is the one which fails
CLASS_I2CIO(char *x1, int y1, int Width, int Height);

private:
char *device;
int address;
int width, height;

public:
virtual ~CLASS_I2CIO();
int FileDescriptor = 0;

// class variables
\_\_u8 reg;  /\* Device register to access \*/
\_\_s32 res;
char buffer\[10\]= { }; // clear buffer  - was not initialized

k5054

Vaclav_ wrote:

The error "points " to #define which is redefined in this class - temporary for test purposes.

Are you doing something like this?

#include "spi.h" // #defines DEVICE_SPI, etc

#define DEVICE_SPI_"dev/spidev0.0" // Temporary define

class C_VNA {
// ...
};

That would mean that you're re-defining DEVICE_SPI, but normally your compiler should warn about redifines. Maybe you need #undef where you set up your temp defines. e.g.

#ifdef DEVICE_SPI
#define ORIG_DEVICE_SPI DEVICE_SPI
#undef DEVICE_SPI
#endif
#define DEVICE_SPI "dev/spidev0.0"
// your code here that uses the temporary DEVICE_SPI

#ifdef ORIG_DEVICE_SPI
#undef DEVICE_SPI
#define DEVICE_SPI ORIG_DEVICE_SPI
#undef ORIG_DEVICE_SPI
#endif

Lost User

That is incomplete, and will not even compile, so it is impossible to guess what else may be wrong. [edit] See Graham's answer below. [/edit]

Graham Breach

Inside a function, this declares a variable called i2c_ads1115 with type CLASS_I2CIO and calls the constructor with the two values DEVICE_I2C and ADDRESS_ADS:

CLASS_I2CIO i2c_ads1115(DEVICE_I2C,ADDRESS_ADS);

Inside a class definition it declares a member function called i2c_ads1115 that returns a CLASS_I2CIO type and takes two arguments, which is where the compiler is having problems. Instead of DEVICE_I2C being a type, you have a #defined string. To get i2c_ads1115 as a member variable, declare it the same way as the i2c_ioctl member variable, then construct it with arguments in the initialization list of the C_VNA class.

Vaclav_

Thanks, I'll give it a go. One more question. Why I have no issue with using same syntax making an instance of the class in main ()? Stupid question - could I just change the #define to "include" type ?

Graham Breach

I can't say why that syntax defines a variable using a constructor in one place and declares a member function in another - you would have to ask the people who designed C++ that. Making the #define include the type would probably give you a different error message, but it would still be attempting to declare a member function.

Stefan_Lang

The compiler expects a function signature, but the function arguments you specified are missing a type. Try somthing like this

CLASS_I2CIO i2c_ads1115_test(const char* DEVICE_I2C, int ADDRESS_ADS);

(not sure what type the second argument is supposed to be)

GOTOs are a bit like wire coat hangers: they tend to breed in the darkness, such that where there once were few, eventually there are many, and the program's architecture collapses beneath them. (Fran Poretto)

Stefan_Lang

CLASS_I2CIO(char Device, int Address);

Surely you mean char* Device, not char Device? If the erroneous line is supposed to be an initialization of a variable calling this constructor, then that is not going to work: you can not initialize a member variable right inside the class declaration, unless it is static. Instead you have to do the initialization inside the constructor, like this:

class C_VNA {
C_VNA();
...
CLASS_I2CIO i2c_ads1115_test; // just declaring the type of the member variable here
};
...
// constructors
// initialize the class members here (only needed when not using default constructor)
C_VNA::C_VNA()
: i2c_ads1115_test(DEVICE_I2C,ADDRESS_ADS)
{
// more initialization code
}

[edit2]reintroduced tags [/edit]

Lost User

Stefan_Lang wrote:

had to remove tags - for some reason they are not working!?

Look at the checkboxes below the edit window. Do you have "Treat my content as plain text, not as HTML" set?

Stefan_Lang

Thanks, that was indeed the problem. No idea why it was checked - I almost always use tags. :confused: GOTOs are a bit like wire coat hangers: they tend to breed in the darkness, such that where there once were few, eventually there are many, and the program's architecture collapses beneath them. (Fran Poretto)

Vaclav_

Second argument function is an I2C device address = in this case A/D converter ADS1115.