DOC: Overview Manual Documents PostAppMessage Incorrectly (86266)


The information in this article applies to:

  • Microsoft Windows Software Development Kit (SDK) 3.1
This article was previously published under Q86266
3.10 WINDOWS kbprg kbdocerr

SUMMARY

Section 1.1.4 (page 10) of the "Microsoft Windows Software Development Kit: Programmer's Reference, Volume 1: Overview" manual for version 3.1 documents that the PostAppMessage function posts a message to an application using its module handle. This statement is incorrect; PostAppMessage posts a message to an application using its task handle.

MORE INFORMATION

Microsoft Windows makes a very important distinction between a task handle and a module handle. Each instance of an application has exactly one task, which consists of a stack, a message queue, and an execution state (CPU registers). However, all instances of an application share the same module, which consists of the application's executable code and resources.

One cannot post a message to a module for two reasons:

  • A module does not have a message queue; therefore, it cannot process a message.
  • Potentially, several application instances (tasks) share a module; therefore, a module handle does not identify a unique task to receive the message.
By posting a message to a task handle, the message is sent to only one instance of an application.
Modification Type:MinorLast Reviewed:2/14/2005
Keywords:kb16bitonly kbdocfix kbWndw KB86266
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