Shared Memory

The Shared Memory component provides cross-platform access to shared memory.

This module makes it simple to employ shared memory in Qt applications. Shared memory can be used for high-speed inter-process communication. It provides a portable, platform-independent class API to the shared memory mechanism of the underlying operating system, and implements a locking mechanism to ensure safe access from multiple concurrent processes.

This Qt Solutions component is for Qt 4. For Qt 3 Solutions, please visit the Qt 3 Solutions Catalog.

Documentation:

Classes

• QtSharedMemory

• Shared memory between threads
• Shared memory between processes

Tested on:

• Qt 4.3.0 / Windows XP / MSVC.NET 2003
• Qt 4.3.0 / Windows Vista / MSVC.NET 2005
• Qt 4.3.0 / Linux / gcc
• Qt 4.3.0 / MacOS X 10.4 / gcc

Unsupported platforms:

Only the tested platforms are supported, however the classes should be platform independent and are likely to work on the platforms supported by Qt.

Download Commercial Edition:

Only available for Qt Solutions license holder with a valid Support and Maintenance agreement (authentication required).

• qtsharedmemory-2.4_1-commercial.zip
• qtsharedmemory-2.4_1-commercial.tar.gz

Changes:

• 2.4: Windows: Bugfix; avoid leakage of semaphore handles.
• 2.3: Unix: Bugfix; handle 0 shm and semaphore ids.
• 2.3: Make size() work.
• 2.3: Windows: Fix bug that could cause distinct names to map to same segment.
• 2.3: Compilation fixes for MinGW.
• 2.2: Windows: Avoid including windows.h in header file.
• 2.1: Windows: Support attaching in readonly mode.
• 2.1: Windows: Improved speed and robustness.
• 2.0: Version 1.1 ported to Qt 4.