Microsoft KB Archive/171143

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HOWTO: Pass Arguments to a Service

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Q171143

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The information in this article applies to:


 * Microsoft Win32 Application Programming Interface (API), used with:
 * the operating system: Microsoft Windows NT, versions 3.51, 4.0
 * the operating system: Microsoft Windows 2000

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SUMMARY
A Windows NT service can receive arguments. A demand-started service may receive arguments (also known as service arguments) through the StartService API. The service receives the arguments via its Service_Main, which can be defined as follows:

  void Service_Main(DWORD dwArgc, LPTSTR *lpszArgv) NOTE: The Service_Main entry point is user defined through the SERVICE_TABLE_ENTRY structure. The first argument passed to the Service_Main indicates the number of parameters passed to the service while the second parameter contains an array of strings containing the arguments. The first string in the array will always be the name of the service. Any additional strings in the array will contain the arguments passed to the service through the StartService API.

MORE INFORMATION
Sometimes an auto-started service may want to receive arguments. Unfortunately, there is no method to pass arguments to a service through it's Service_Main. These arguments can only be passed to a service through it's main. (This entry point is defined by the user via the compiler. The default entry point is named main.) You can setup the arguments when you install the service through the CreateService API. For example, to pass the arguments "franki" and "hosun" to an auto-started service, you would pass the following string as the lpBinaryPathName parameter of CreateService:

"'d:\\foo\\foo.exe franki hosun'" When the service starts, it can obtain these arguments via its main through argc and argv. To modify the arguments to a service, you call the ChangeServiceConfig API and modify the lpBinaryPathName parameter.

If you have configured your service to run as a shared service, each service originating from the service process will receive the same arguments when it is auto-started. You cannot pass unique arguments to each of the services using main. The services will either have to create a file or registry key to pass unique arguments to each of the services being shared.

Additional query words:

Keywords : kbprogramming kbKernBase kbOSWin2000 kbService kbDSupport kbGrpDSKernBase

Issue type : kbhowto

Technology : kbAudDeveloper kbWin32sSearch kbWin32API