Thread: Question on Accessing parallel port

Hello,
I am trying to access parallel port with C++ on Windows XP. I already have inpout32.dll sitting in my Windows/system32 directory. The problem i encounter is that my complier BloodShed Dev C++ does not recognize inportb or outportb functions no matter what i include as a header.

I need to know several things...
1) What functions should i use to access parallel port? and what header file to include? I do not want to use VC++ or Borland, most of the internet websites give examples on those compilers. I like using free compilers

2) How do i use inpout32.dll? Do i have to link to it in my code? if I do, how do I do it? or is it just fine sitiing where it is?

3) Can someone point me to a good resource that describes step by step how to
access parrallel port in free compiler?

I was trying to find any info on using win 32 API funtions to access parallel port.
Whole buch of crap and no specifics...
On the link you provided there is an example for visual basic, i tried it and it gives me runtime error.

Any link that would describe the API functions to access that damn port?

Codeplug has a class based off the win32 api that helps you access the serial port found here:

http://cboard.cprogramming.com/showp...52&postcount=4

BTW, just to make things clear Visual C++ Express Edition is free...

>> I was trying to find any info on using win 32 API funtions to access parallel port
Define "access". Do you want pin-level control? Or you do you want to communicate with a IEEE-1284 device?

For pin-level access, there isn't really a Win32 API for doing that - other than the MS-CRT functions _inp() and _outp(). MinGW uses the MS-CRT so these functions are available to you. The problem is that the "in" and "out" instructions are privileged under NT OS's. The inpout32 DLL provides two interfaces, Inp32() and Out32(), which somehow overcome this problem. Here's sample code that loads the library dynamically and uses those functions: http://www.hytherion.com/beattidp/comput/pport/Test1.c

Another option (for pin-level access) is to use GiveIO or UserPort, which gives user-mode processes "permission" to use the "in" and "out" instructions - which mean you can use the MS-CRT functions: _inp() and _outp() (from conio.h).

If you just want to communicate with a IEEE-1284 device, you can use CreateFile() on the dos-device name for the port, like "LPT1". Then use ReadFile() and WriteFile() normally. Or if you really want to keep is simple, you could try using standard stream I/O on the file "LPT1".

>> On the link you provided there is an example for visual basic...
There are a lot more resources than that when you use Salem's link as a starting point.

gg