PROGMEM problem in PTP library

Projects Programming
1

Hi,

I want to use the PTP library to use a camera with the USB host shield 2.0. First step was to build the example PTPDevInfo with Arduino 1.6.5 ide. But the compiler stops with an error

devinfoparser.cpp:145:38: error: variable 'DevInfoParser::imNames' must be const 
in order to be put into read-only section by means of '__attribute__((progmem))' 
const char* DevInfoParser::imNames[] PROGMEM =

In the source I can see that an array is filled with values out of the flash.

const char msgEXIF_JPEG			[] PROGMEM = "EXIF_JPEG";
const char msgTIFF_EP			[] PROGMEM = "TIFF_EP";
const char msgFlashPix			[] PROGMEM = "FlashPix";
const char msgBMP				[] PROGMEM = "BMP";
const char msgCIFF				[] PROGMEM = "CIFF";
const char msgUndefined_0x3806	[] PROGMEM = "Undefined_0x3806";
const char msgGIF				[] PROGMEM = "GIF";
const char msgJFIF				[] PROGMEM = "JFIF";
const char msgPCD				[] PROGMEM = "PCD";
const char msgPICT				[] PROGMEM = "PICT";
const char msgPNG				[] PROGMEM = "PNG";
const char msgUndefined_0x380C	[] PROGMEM = "Undefined_0x380C";
const char msgTIFF				[] PROGMEM = "TIFF";
const char msgTIFF_IT			[] PROGMEM = "TIFF_IT";
const char msgJP2				[] PROGMEM = "JP2";
const char msgJPX				[] PROGMEM = "JPX";

...
...

const char* DevInfoParser::imNames[] PROGMEM = 
{
	msgUndefined,
	msgEXIF_JPEG,			
	msgTIFF_EP,			
	msgFlashPix,			
	msgBMP,				
	msgCIFF,				
	msgUndefined_0x3806,	
	msgGIF,				
	msgJFIF,				
	msgPCD,				
	msgPICT,				
	msgPNG,				
	msgUndefined_0x380C,	
	msgTIFF,				
	msgTIFF_IT,			
	msgJP2,				
	msgJPX,				
};

I try to fix the problem with the help of PROGMEM reference. But I got no luck

const char* const DevInfoParser::imNames[] PROGMEM = 
{
	msgUndefined,
...

results in

devinfoparser.cpp:145:44: error: declaration of 'const char* DevInfoParser::imNames []' 
outside of class is not definition [-fpermissive] const char* const DevInfoParser::imNames[] PROGMEM =

Has someone an idea how to fix it?

Thanks

Mark

2

Has someone an idea how to fix it?

The array appears to be a class member. In the header file, it is defined one way. You changed the source file to declare it differently. The definition needs to be the same in both files.

3

Hello Paul,

thanks for help. :blush: you are so right. I did not think on the declaration. If I change

class DevInfoParser : public PTPReadParser
{
	static const char* ptpopNames[];
	static const char* mtpopNames[];
	static const char* ptpevNames[];
	static const char* mtpevNames[];
	static const char* acNames[];
	static const char* imNames[];
	...

to

class DevInfoParser : public PTPReadParser
{
	static const char* const ptpopNames[];
	static const char* const mtpopNames[];
	static const char* const ptpevNames[];
	static const char* const mtpevNames[];
	static const char* const acNames[];
	static const char* const imNames[];
	...

the compiler is happy.

Thanks

Mark