PDDREF:Linking Resource Manager Services
This section discusses the programming considerations of adding Resource Management services to your driver.
The OS/2 Resource Manager consists of three components: RESOURCE.SYS, RMCALLS.LIB, and RMINFO.DLL.
RESOURCE.SYS
RESOURCE.SYS is a base device driver. In OS/2 Warp and subsequent versions, this driver is provided as part of the product and is loaded automatically without an explicit CONFIG.SYS BASEDEV= statement.
RMCALLS.LIB
The RMCALLS library code linked to a driver will provide rudimentary support for cases in which RESOURCE.SYS is not loaded on a system. Typically, a handle value of -1L and a return code of RMRC_SUCCESS will occur. In this manner, the driver code might not need to know about the presence of RESOURCE.SYS on a system, and can assume that all resources are available. This was the behavior previous to implementing Resource Manager.
RMADDToHDevice ³RMAdjToHandleList ³RMAllocResource ³ RMConvertID ³RMCreateAdapter ³RMCreateDetected ³ RMCreateDevice ³RMCreateDriver ³RMCreateLDev ³ RMCreateSysName ³RMDeAllocResource ³RMDestroyAdapter ³ RMDestroyDetected ³RMDestroyDevice ³RMDestroyDriver ³ RMDestroyLDev ³RMDestroySysName ³RMDevIDToHandleList ³ RMGetCommandLine ³RMGetDriverName ³RMGetNodeInfo ³ RMGetVersion ³RMHandleToParent ³RMHandleToResourceHandleList ³ RMHandleToType ³RMHDevToHLDev ³RMKeyToHandleList ³ RMModifyNodeFlags ³RMModifyResources ³RMParseSCSIInquiry ³ RMResToHandleList ³RMUpdateAdjunct
RMCALLS Library Data
The RMCALLS library references the following four variables:
PFN Device_Help; ULONG RMFlags = NULL; PFNRM RM_Help0 = NULL; PFNRM RM_Help3 = NULL;
The PFN Device_Help variable must be initialized by your driver prior to calling any Resource Manager services. It is expected to contain the Device Help entry point provided in the OS/2 Init Request Packet your driver receives.
Prior to calling any Resource Manager services, the remaining data variables must be initialized to zero. Specify C-initializers when declaring the variables.
These variables must be allocated by your driver. If you plan to use Resource Manager services after your driver has completed initialization, you must ensure that these variables are not discarded.
Note: If you do not declare these variables, a linker error message will occur, indicating that they are missing.
RMCALLS Library Code
The code portion of the RMCALLS library is included in a segment named RMCode. There are three alternatives in handling the code in this segment:
- Combine RMCode with your driver's default code segment if your driver does not intend to use Resource Manager services after initialization. Because the library code is linked after OBJ text, it would be discarded as your driver discards its initialization code.
- Combine RMCode with your driver's swappable code segment. If your driver intends to use Resource Manager services after its initialization and has a swappable code segment, then combine RMCode with this segment.
- Place RMCode in its own swappable segment. If your driver does not have a swappable code segment, then the RMCode will reside in its own swappable segment by default.
RMINFO.DLL
The RMINFO.DLL is dynamically linked with ring 3 applications to provide an interface with RESOURCE.SYS. The interfaces listed in the following table can be called from 16- and 32-bit applications.
RMAllocResource ³RMConvertID ³RMCreateAdapter ³ RMCreateDetected ³RMCreateDriver ³RMDeAllocResource ³ RMDeleteDetectedData ³RMDestroyDetected ³RMDestroyDriver ³ RMDevIDToHandleList ³RMGetNodeInfo ³RMGetSnoopLevel ³ RMHandleToResourceHandleList ³RMSaveDetectedData ³RMSetSnoopLevel
Resource Manager Services
This section lists and describes the Resource Manager services and their return codes.
The following Resource Manager services are grouped functionally and are provided by a library. The information in this library can be found in Linking Resource Manager Services.