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MethProv
This sample
demonstrates the framework necessary to implement a methods provider. This
provider supports methods for the class "TestMeth". The only method supported in this sample is named
Echo. It takes an input string, copies
it to the output string and places the length of the string in the method
return value. Note that the method is
marked as "Static" and so it can be executed using a path to either
an instance of the class, or the class path.
The MOF definition of
the MethProvSamp class is:
[dynamic:
ToInstance, provider("MethProv")] class MethProvSamp
{
[implemented, static]
uint32 Echo([IN]string
sInArg="default", [out] string sOutArg);
};
NOTE: The
MethProv sample can be used in conjunction with another WMI SDK sample,
MethCli, the sample method client.
Please refer to the MethCli documentation for details. The MethProv provider sample can also be
used separately with other WMI tools such as CIM Studio without building the
MethCli sample.
Building the Provider DLL
The DLL can be built
from the command line using NMAKE, or it can be built using Microsoft Visual
C++.
From the command line
in the sample installation directory, type the following:
NMAKE /f "Makefile"
From Microsoft Visual
C++:
1. Select File + Open Workspace
2. Select the MethProv.DSP file
Registering the DLL and Class
1. The DLL must be registered with COM. From the
command line in the sample installation directory, type the following:
REGSVR32 MethProv.dll
2. You must also compile the MOF in order to make the
WMI CIMOM aware of the class. From the
command line in the sample installation directory, type the following:
MOFCOMP methprov.mof
Using Method Client Application
(MethCli) to Access the Sample
In order to use the MethCli sample to test the MethProv sample, follow the instructions provided in the MethCli documentation to build and execute the MethCli sample method client.
General Notes
Things
to remember when you're building your own WMI provider:
1.
WMI interfaces are defined
in wbemcli.h and wbemprov.h found in the wmi\include directory. You may #include both these files by
including just wbemidl.h located in the same directory.
2.
WMI interface CLSIDs are
defined in wbemuuid.lib. If you get unresolved externals in interfaces and
CLSIDs, this is what is missing.
3.
You'll need to link with oleaut32.lib
and ole32.lib to get the needed COM support.
4.
In the Link|Output
settings, specify 'wWinMainCRTStartup' as the entry point. This is per the
Unicode programming instructions.
5.
If you're using the makefiles, don't forget to set the Visual C++
environment variables. This is done by running VCVARS32.BAT.