How to get the number of the printer port ?

[Zaph-0]

My program needs to find out the resource number of lpt1: which can be different from computer to computer. It is usually something like 0x278 or 0x378...

Can someone please help me with this ?

[Krishnaa]

Look at WMI class Win32_Printer.
http://msdn.microsoft.com/library/en...asp?frame=true

http://www.codeproject.com/system/UsingWMI.asp

[Zaph-0]

Hi,

I did take a look at it, but all that I can see is that I can get the name of the printer ports like "lpt1" and I can get that already with enumports. What I need is the corresponding hardware resource port adress (0x278, 0x378, etc...).

But thanks anyway...

[Zaph-0]

I found a way to enumerate the number of the real lpt ports and find the matching port addresses.

If anybody wants to know the solution let me know and I will upload it...

[jayender.vs]

I found a way to enumerate the number of the real lpt ports and find the matching port addresses.
If anybody wants to know the solution let me know and I will upload it...

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 ..

[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...

[pradish]

To find Printer port address

Step 1, Go to the command prompt
Type debug

ex:

c:\ debug

the prompt will change to "-"

Then type the following

- 0004:0008 l8

All four port address will be displayed( i forgot the order).
Mind you it is (L8) not (one 8), in the above command

i know, this was not the solution you were expecting, may be you may
get new ideas to solve your problem.

regards
pradish