How to get the number of the printer port ?

[Zaph-0]

Thats so nice u dude... and nothing wrong in sending the code now as it might use for someone latter when they search this forum ..

Well, I needed this function because I am controlling a robot arm with avr microprocessors connected to the parallel port. I didn't find anything on the net on how to get the port adresses automatically which would mean I would have to set the parallel port adress manually and I didn't like that. So I had to get a little "creative" with the registry...

I tried it on several computers with different settings for the parallel port (including automatic setting, boot setting and forced setting) and it always worked for me.

If someone uses it and finds a mistake please let me know...


But here you go:

int * CMicrobotView::GetPortAddresses()
{	HKEY	key1;
	HKEY	key2;
	int		i,x;
	char	buffer[2000];
	char	branch1[300];
	char	branch2[300];
	int		type,size;
	int *	list;
	//
	if(RegOpenKeyEx(HKEY_LOCAL_MACHINE, "SYSTEM\\CurrentControlSet\\Enum\\ACPI", NULL, KEY_READ, &key1) != ERROR_SUCCESS)
	{	return NULL;
	}
	//
	list = new int[2*10 + 1];
	x = 0;
	//	Enumerate HW
	for(i=0;(RegEnumKey(key1, i, buffer, sizeof(buffer)) == ERROR_SUCCESS) && (x<10); i++)
	{	if((strlen("SYSTEM\\CurrentControlSet\\Enum\\ACPI") + strlen(buffer)) < (sizeof(branch1) - 2))
		{	sprintf(branch1, "SYSTEM\\CurrentControlSet\\Enum\\ACPI\\%s\\", buffer);
			//	Enter HW-Tree
			if((RegOpenKeyEx(HKEY_LOCAL_MACHINE, branch1, NULL, KEY_READ, &key2) != ERROR_SUCCESS)
			|| (RegEnumKey(key2, 0, buffer, sizeof(buffer)) != ERROR_SUCCESS))
			{	RegCloseKey(key2);
				continue;
			}
			strcat(branch1,buffer);
			//	Check Device Parameters
			size = sizeof(buffer);
			sprintf(branch2,"%s\\Device Parameters", branch1);
			if((RegOpenKeyEx(HKEY_LOCAL_MACHINE, branch2, NULL, KEY_READ, &key2) != ERROR_SUCCESS)
			|| (RegQueryValueEx(key2, "PortName", 0, (DWORD*)&type, (BYTE*)buffer, (DWORD*)&size) != ERROR_SUCCESS)
			|| (strncmp(buffer,"LPT",3) != 0))
			{	RegCloseKey(key2);
				continue;
			}
			list[x+1+0] = buffer[3]-'0';
			//	Portname found -> Extract Data
			RegCloseKey(key2);
			size = sizeof(buffer);
			sprintf(branch2,"%s\\LogConf", branch1);
			if(RegOpenKeyEx(HKEY_LOCAL_MACHINE, branch2, NULL, KEY_READ, &key2) != ERROR_SUCCESS)
			{	RegCloseKey(key2);
				continue;
			}
			//	
			if((RegQueryValueEx(key2, "ForcedConfig", 0, (DWORD*)&type, (BYTE*)buffer, (DWORD*)&size) == ERROR_SUCCESS)
			|| (RegQueryValueEx(key2, "BootConfig"  , 0, (DWORD*)&type, (BYTE*)buffer, (DWORD*)&size) == ERROR_SUCCESS))
			{	list[x+1+1] = ((BYTE)buffer[24]) + ((BYTE)buffer[25]) * 0x100;
				x++;
			}
			else
			{	if(RegQueryValueEx(key2, "BasicConfigVector", 0, (DWORD*)&type, (BYTE*)buffer, (DWORD*)&size) == ERROR_SUCCESS)
				{	list[x+1+1] = buffer[57] * 0x100 + buffer[56];
					x++;
				}
			}
			//
			RegCloseKey(key2);
		}		
	}
	RegCloseKey(key1);
	//
	if(x == 0)
	{	delete [] list;
		return NULL;
	}
	list[0] = x;
	return list;
}

The return value is either NULL if it couldn't find anything or an array of ints with the first value the number of parallelports and then pairs of ints describing the lpt number and the serial adress. You have to delete the array if you don't need it anymore or it will result in a memory leak.

example:

list[0] = 2 -> number of parallel ports found (up to 10)
list[1] = 1 -> lpt1:
list[2] = 0x2f8 -> serial adress 0x278
list[3] = 2 -> lpt2:
list[4] = 0x3f8 -> serial adress 0x378


Have fun...