?
Solved

Wininet & multithreaded

Posted on 1997-06-13
8
Medium Priority
?
525 Views
Last Modified: 2013-12-03
I wrote a class that uses wininet to implemenet FTP session ,
but I need to have 5-6 objects of the same class running
simultaniasly , as a one thread program it did the job
perfectly , but when trying to have multiple threads , I had
many problems , ranging from unknown phenomenas to some
wierd things , like InternetConnect get stuck or only returns after 60 seconds and reporting a TIMEOUT , while
I know for sure that the destination is reachable , I know
that some function in Wininet need to be synchronized for
multithreaded operations , but which ones and how ? there
is nothing in MS documentation , plus if you know a good
disscusion forums or a tutorial ( more serious then MS documents) let me know

thanks
Moshe
0
Comment
Question by:moshem
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
8 Comments
 
LVL 23

Expert Comment

by:chensu
ID: 1398281
MFC 4.2 and later have some classes that implement FTP session using Wininet functions. They are CInternetSession, CInternetConnection, CFtpConnection, CFtpFileFind, ... I think you can refer to the source code to find out how to do it.
0
 
LVL 1

Author Comment

by:moshem
ID: 1398282
Thanks for the pointer , but I really can't spend the time digging throu the huge MFC classes , I need a reliable answer withouth that overhead , please try to answer within the Win32
SDK boundaries

thanks
0
 
LVL 1

Author Comment

by:moshem
ID: 1398283
Adjusted points to 150
0
Prepare for your VMware VCP6-DCV exam.

Josh Coen and Jason Langer have prepared the latest edition of VCP study guide. Both authors have been working in the IT field for more than a decade, and both hold VMware certifications. This 163-page guide covers all 10 of the exam blueprint sections.

 
LVL 1

Expert Comment

by:dtowell
ID: 1398284
My guess is that WinINet is conpletely nonthreadaware, meaning you will need to synchronize access yourself.
0
 
LVL 1

Author Comment

by:moshem
ID: 1398285
Sorry , but I refer you to the WinInet SDK to a specific
paragraph that specifies that wininet is multitheaded ready!
0
 
LVL 3

Accepted Solution

by:
vinniew earned 300 total points
ID: 1398286
WinInet compiles down to using asynchronous sockets.  I would suggest that you probably made the error yourself.  Be sure to specify different port addresses for each connection that's outbound, because the data channel will come back and look for it.  If it's busy with other data, it will get confused.
0
 
LVL 1

Author Comment

by:moshem
ID: 1398287
what do you mean by "Be sure to specify different port addresses for each connection that's outbound.." , what is that in
wininet API
0
 
LVL 3

Expert Comment

by:vinniew
ID: 1398288
in FTPConnect you can specify port number.  That's a good starting point.  I looked through the inet.cpp class and MS doesn't worry about port numbers.  I'm not totally sure why.  I'm accustomed to doing all this with Winsock, because I have more control.  In Winsock, you connect(), bind() , send a command, recv().  Have you tried using the MFC classes to do this yet?  They may have support for multiple threads built in.
0

Featured Post

On Demand Webinar: Networking for the Cloud Era

Ready to improve network connectivity? Watch this webinar to learn how SD-WANs and a one-click instant connect tool can boost provisions, deployment, and management of your cloud connection.

Question has a verified solution.

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

This tutorial is about how to put some of your C++ program's functionality into a standard DLL, and how to make working with the EXE and the DLL simple and seamless.   We'll be using Microsoft Visual Studio 2008 and we will cut out the noise; that i…
With most software applications trying to cater to multiple user needs nowadays, the focus is to make them as configurable as possible. For e.g., when creating Silverlight applications which will connect to WCF services, the service end point usuall…
This is Part 3 in a 3-part series on Experts Exchange to discuss error handling in VBA code written for Excel. Part 1 of this series discussed basic error handling code using VBA. http://www.experts-exchange.com/videos/1478/Excel-Error-Handlin…
Monitoring a network: how to monitor network services and why? Michael Kulchisky, MCSE, MCSA, MCP, VTSP, VSP, CCSP outlines the philosophy behind service monitoring and why a handshake validation is critical in network monitoring. Software utilized …

719 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