OpenServiceA function (winsvc.h)

Article
02/09/2023

Opens an existing service.

Syntax

SC_HANDLE OpenServiceA(
  [in] SC_HANDLE hSCManager,
  [in] LPCSTR    lpServiceName,
  [in] DWORD     dwDesiredAccess
);

Parameters

[in] hSCManager

A handle to the service control manager database. The OpenSCManager function returns this handle. For more information, see Service Security and Access Rights.

[in] lpServiceName

The name of the service to be opened. This is the name specified by the lpServiceName parameter of the CreateService function when the service object was created, not the service display name that is shown by user interface applications to identify the service.

The maximum string length is 256 characters. The service control manager database preserves the case of the characters, but service name comparisons are always case insensitive. Forward-slash (/) and backslash (\) are invalid service name characters.

[in] dwDesiredAccess

The access to the service. For a list of access rights, see Service Security and Access Rights.

Before granting the requested access, the system checks the access token of the calling process against the discretionary access-control list of the security descriptor associated with the service object.

Return value

If the function succeeds, the return value is a handle to the service.

If the function fails, the return value is NULL. To get extended error information, call GetLastError.

The following error codes can be set by the service control manager. Others can be set by the registry functions that are called by the service control manager.

Return code	Description
ERROR_ACCESS_DENIED	The handle does not have access to the service.
ERROR_INVALID_HANDLE	The specified handle is invalid.
ERROR_INVALID_NAME	The specified service name is invalid.
ERROR_SERVICE_DOES_NOT_EXIST	The specified service does not exist.

Remarks

The returned handle is only valid for the process that called OpenService. It can be closed by calling the CloseServiceHandle function.

To use OpenService, no privileges are required aside from SC_MANAGER_CONNECT.

Examples

For an example, see Starting a Service.

Note

The winsvc.h header defines OpenService as an alias which automatically selects the ANSI or Unicode version of this function based on the definition of the UNICODE preprocessor constant. Mixing usage of the encoding-neutral alias with code that not encoding-neutral can lead to mismatches that result in compilation or runtime errors. For more information, see Conventions for Function Prototypes.

Requirements

Requirement	Value
Minimum supported client	Windows XP [desktop apps only]
Minimum supported server	Windows Server 2003 [desktop apps only]
Target Platform	Windows
Header	winsvc.h (include Windows.h)
Library	Advapi32.lib
DLL	Advapi32.dll

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