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»Forums Index »Product Support »IQFeed 3rd Party Software Support »IQFeed Client and IPWorks - Free Heap Block Error
Author Topic: IQFeed Client and IPWorks - Free Heap Block Error (3 messages, Page 1 of 1)

-Interested User-
Posts: 2
Joined: May 8, 2012

Posted: May 8, 2012 01:45 AM          Msg. 1 of 3

I am a 3rd party developer using ipworks ( TCP/IP Delphi component to connect to IQFeed 4.8 ( using sockets on localhost (

I am making a request for history to the IQFeed client (HD,... ) and once the history is received, I disconnect the socket and free the socket connection.

PROBLEM: After I free the socket (IPWorks Socket) in our program, IQFeed outputs the following in the outputdebug log.

HEAP: Free Heap block 1da81da0 modified at 1da81e2c after it was freed
Ignoring Non-user Breakpoint at $76FD04E5.

If I do not free the socket (and cause a memory leak) the error does not occur.

It appears that IQFeed is modifying some memory after its been free'd.

Any thoughts ?

p.s. When this error occurs we sometime get random memory problems in the program as the memory that is over written is sometimes being used by something else.

-DTN Guru-
Posts: 2034
Joined: Nov 21, 2005

Posted: May 11, 2012 01:44 PM          Msg. 2 of 3
Sorry for the delay responding but this is not likely to be anything in IQConnect itself (although if it is, it is certainly something we would like to track down).

What is outputting the debug log?
Other than the fact that it happens when you shut down your end of the socket, do you have anything that points to this actually being something in IQConnect as opposed to the socket control you are using?

-Interested User-
Posts: 2
Joined: May 8, 2012

Posted: May 14, 2012 12:57 AM          Msg. 3 of 3
I am note sure what is generating the outputdebug, I thought it might be the iqfeed client actually.

I have not had this problem with the socket control for other projects.


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