Solved

CreateProcess and WaitForSingleObject fails on the second of two PDF files

Posted on 2009-04-14
2
537 Views
Last Modified: 2012-05-06
All
I use CreateProcess and WaitForSingleObject in Delphi 2007 to open files and wait for them to be closed.
I have found that when I open two PDF files in a row, the second WaitForSingleObject returns immediately. I have also found that this happens for jpg and tif files but not txt files. Also the second PDF takes 10 seconds longer to open than if opened by itself!
It also happens on both Vista and XP, and on a range of computers.
Am I using CreateProcess incorrectly or is it something else?

Any help would be appreciated.

Regards

Bob

if CreateProcess(nil, PChar(sText), nil, nil, False,

    NORMAL_PRIORITY_CLASS, nil, pFilePath, myStartupInfo, myProcessInfo) then begin

    WaitForSingleObject(myProcessInfo.hProcess, INFINITE);

    CloseHandle(myProcessInfo.hProcess);

    CloseHandle(myProcessInfo.hThread);

end;

Open in new window

0
Comment
Question by:beezee
2 Comments
 
LVL 7

Accepted Solution

by:
ahalya earned 500 total points
ID: 24175000
I guess what probably is happening is that your second call creates a second instance of Acrobact Reader, which is terminating immediately  (once it figures out a previous instance is running). The second instance probably is passing the file name to the first instace of the Acrobat Reader which opens the file (but is a separate process).

Your wait returns when the second process is terminated after passing the filename

0
 

Author Closing Comment

by:beezee
ID: 31570197
ahalya
Thanks for that. I added the /n switch to Acro32.exe and it solved the problem.

Regards

Bob
0

Featured Post

Is Your Active Directory as Secure as You Think?

More than 75% of all records are compromised because of the loss or theft of a privileged credential. Experts have been exploring Active Directory infrastructure to identify key threats and establish best practices for keeping data safe. Attend this month’s webinar to learn more.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Have you ever had your Delphi form/application just hanging while waiting for data to load? This is the article to read if you want to learn some things about adding threads for data loading in the background. First, I'll setup a general applica…
Introduction Raise your hands if you were as upset with FireMonkey as I was when I discovered that there was no TListview.  I use TListView in almost all of my applications I've written, and I was not going to compromise by resorting to TStringGrid…
With the power of JIRA, there's an unlimited number of ways you can customize it, use it and benefit from it. With that in mind, there's bound to be things that I wasn't able to cover in this course. With this summary we'll look at some places to go…
The is a quite short video tutorial. In this video, I'm going to show you how to create self-host WordPress blog with free hosting service.

911 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

21 Experts available now in Live!

Get 1:1 Help Now