Problems with mainframe emulator using EHLLAPI

Question

Hi there I am using EHLLAPI to connect to a mainframe emulator. I can connect to the session and do some major commands (e.g. connect disconnect get cursor set cursor sendkey copy ps to string etc.). The emulator is Rumba version 5.2. What I can't get my Windows app to do is to chain a bunch of commands together. For example: I want to loop where I use Sendkey then SetCursor the Sendkey SetCursor Copy PS to String etc.). I can't get the chain of commands to work only the first two or so work and then nothing. Thanks in advance.

Dennis Durham · Answer

You'e quite welcome I'm just sorry my reply wasn't timely (but hope it may provide help in the future). I found the thread while trying to find a better way to use EHLLAPI in VB.NET!

Sam Hobbs · Answer

Thank you Dennis; I wish I had been able to provide that answer but you know EHLLAPI much better than I do. I heard people talking about it back in the late 1980's but other than that about the only thing I know is that it is an IBM high-level API for communications. I assume it is part of SNA but it pre-dates SAA and I assume that SAA provides a higher-level interface.

Dennis Durham · Answer

Rather than using the System timer your EHLLAPI most likely has a Wait function (it's function 4 I believe). The benefit to using the EHLLAPI function is that it watches for the system to become available instead of waiting for a specified time (which may not be sufficient).

Sam Hobbs · Answer

Note that Rumba is not a mainframe emulator; it is a mainframe terminal emulator. I would have understood better quicker what it is that you are doing if you had called it a terminal emulator. Rumba emulates 3270 (and 5250?) style of dumb terminals; I am quite familiar with 3270 terminals having used real ones for about ten years.

Sam Hobbs · Answer

Okay so you used Sleep; I was not aware of a function called wait but I of curse knew about Sleep. Hopefully that is all you need to do. The thing I don't know is if the amount of time to wait will be consistent; if you don't wait enough time it won't work and if you use a wait period long enough to work for most or all situations then you might be waiting longer than needed for most times. I don't know; that is for you to determine.

Brian · Answer

It turns out that I did need to wait a few before using SendKey. I fixed the issue with this: System.Threading.Thread.Sleep(500); I put this at the top of my SendKey method. Resolved. Thanks.

Sam Hobbs · Answer

The problem is likely unique to Rumba and automating it from another application; it seems unlikely there will be anyone else with experience with that combination. I don't know what Wait function you are looking at. My guess is that you will need to process the Rumba window to determine when something has completed. There might not be a simple solution.

Brian · Answer

Sam I used this example almost verbatim: http://www.codeproject.com/KB/cs/all_ehllapi.aspx The only difference is the .dll that Rumba uses. In that sample code there are a few major functions. I am able to use them successfully. But here is what I want to do when I say chain commands: When a user clicks on one of the buttons on my Windows form I want to call several commands in a row in that click event. For example I want to do the following: Set the cursor send in a string set the cursor send in another string etc. I figured out using some other sample code that the emulator is busy when I'm trying to perform functions back-to-back. I don't know if the Wait function is my answer or not. I am still looking into that. I'm not going to be able to purchase third party software for this solution - the budget doesn't allow for it. If anyone has seen this kind of thing and has any pointers then I'd be happy to hear them. Thanks.

Sam Hobbs · Answer

It sounds to me as if the problems are not related to EHLLAPI at all; you seem to be atempting to control another application. I think I have heard of Rumba; I have never used it but if I have heard about it it has existed for about a quarter of a century. The best solution is to use software that allows you to interface with the mainframe more directly. IBM and third-party developers definitely has other software. Controlling other applications using Sendkey and related functions is not as easy as you would like. I think there is not enough information here for people to help you; you need to provide more information and if you don't have more information you neeed to spend some more time analyzing the problem. Please provide more details about can't get the chain of commands to work.