PDDREF:Device Helper (DevHlp) Services

Physical Device Driver Reference
Introduction Physical Device Driver Overview Physical Device Driver Architecture and Structure OS/2 Physical Device Driver Operations OS/2 Physical Device Driver Design Issues Character Device Monitors Installation of External Loadable Device Drivers Physical Device Driver Strategy Commands Device Helper (DevHlp) Services Resource Management Linking Resource Manager Services Generic IOCtl Commands Appendixes OS/2 Version Compatibility Considerations Running OS/2 Version 1.3 16-Bit PDDs on OS/2 Using Advanced Bios Notices Glossary

Many of the functions of an OS/2 physical device driver are related to system operations rather than to hardware operations. An interface to operating system services is available to physical device drivers through the DevHlp Interface.

The Device Helper (DevHlp) services are listed alphabetically with explanations of the purpose, parameters, and calling conventions of each function.

Using DevHlp Services

Calling the DevHlp Interface Routine from Assembler

Register Usage

State of the Interrupt Flag

Constant Definitions

Calling the DevHlp Interface Routine from C

16:16 Virtual Address Conversion

DevHlp Services and Function Codes

DevHlp Services and Device Contexts

Related DevHlp Services

Advanced BIOS Services

Character Queue Management

PDD-VDD Communications Services

Context Hook Services

Interrupt Management

Memory Management

Monitor Management

Process Management

Processor Mode Services - No longer used in OS/2 2.X.

Request Queue Management

Semaphore Management

System Clock Management

System Services

Timer Services