Windows System Services API Reference

Service Control Manager (SCM) APIs

The Service Control Manager is responsible for starting, stopping, and managing Windows services. These APIs allow applications to query and control service status.

`OpenSCManager`

Opens a connection to the service control manager on the specified computer.

SC_HANDLE OpenSCManager(
  LPCTSTR lpMachineName,
  LPCTSTR lpDatabaseName,
  DWORD   dwDesiredAccess
);

Parameters:

Name	Type	Description
`lpMachineName`	`LPCTSTR`	The name of the target computer.
`lpDatabaseName`	`LPCTSTR`	The name of the service database to open. Usually `ServicesActive`.
`dwDesiredAccess`	`DWORD`	The access rights to the service control manager.

Return Value:

SC_HANDLE: A handle to the service control manager. Returns NULL on failure.

`CloseServiceHandle`

Closes a handle to a service or the service control manager.

BOOL CloseServiceHandle(
  SC_HANDLE hSCObject
);

Parameters:

Name	Type	Description
`hSCObject`	`SC_HANDLE`	A handle to a service or the service control manager.

`EnumServicesStatusEx`

Enumerates services or unavailable service control managers.

BOOL EnumServicesStatusEx(
  SC_HANDLE                  hSCManager,
  SC_ENUM_SERVICE_TYPE       InfoLevel,
  SC_ENUM_SERVICE_STATE      State,
  LPENUM_SERVICE_STATUS_PROCESS lpServices,
  DWORD                      cbBufSize,
  LPDWORD                    pcServicesReturned,
  LPDWORD                    pResumeHandle
);

Parameters:

Name	Type	Description
`hSCManager`	`SC_HANDLE`	A handle to the service control manager.
`InfoLevel`	`SC_ENUM_SERVICE_TYPE`	The type of services to enumerate.
`State`	`SC_ENUM_SERVICE_STATE`	The state of the services to enumerate.
`lpServices`	`LPENUM_SERVICE_STATUS_PROCESS`	A pointer to a buffer that receives the status information.
`cbBufSize`	`DWORD`	The size of the buffer pointed to by `lpServices`.
`pcServicesReturned`	`LPDWORD`	A pointer to a variable that receives the count of services returned.
`pResumeHandle`	`LPDWORD`	A pointer to a variable that specifies the starting point for enumeration.

Registry Service APIs

Interact with the Windows Registry to configure and manage service properties.

`RegOpenKeyEx`

Opens an existing registry key. An application must have the appropriate access rights to the key for the function to succeed.

LONG RegOpenKeyEx(
  HKEY   hKey,
  LPCTSTR lpSubKey,
  DWORD  ulOptions,
  REGSAM samDesired,
  PHKEY  phkResult
);

Parameters:

Name	Type	Description
`hKey`	`HKEY`	A handle to an open registry key.
`lpSubKey`	`LPCTSTR`	The name of the subkey to open.
`ulOptions`	`DWORD`	Reserved; must be zero.
`samDesired`	`REGSAM`	A mask that specifies the desired access rights for the key.
`phkResult`	`PHKEY`	A pointer to a variable that receives a handle to the opened key.

`RegQueryValueEx`

Retrieves the data and type for the specified registry value.

LONG RegQueryValueEx(
  HKEY   hKey,
  LPCTSTR lpValueName,
  LPDWORD lpReserved,
  LPDWORD lpType,
  LPBYTE  lpData,
  LPDWORD lpcbData
);

Parameters:

Name	Type	Description
`hKey`	`HKEY`	A handle to an open registry key.
`lpValueName`	`LPCTSTR`	The name of the registry value to query.
`lpReserved`	`LPDWORD`	This parameter is reserved and must be `NULL`.
`lpType`	`LPDWORD`	A pointer to a variable that receives the type code.
`lpData`	`LPBYTE`	A pointer to a buffer that receives the value's data.
`lpcbData`	`LPDWORD`	A pointer to a variable that specifies the size of the buffer pointed to by `lpData`.

Service Management Functions

APIs for creating, deleting, starting, and stopping services.

`CreateService`

Creates a service entry in the specified service control manager database and returns a handle to the service.

SC_HANDLE CreateService(
  SC_HANDLE hSCManager,
  LPCTSTR lpServiceName,
  LPCTSTR lpDisplayName,
  DWORD   dwDesiredAccess,
  DWORD   dwServiceType,
  DWORD   dwStartType,
  DWORD   dwErrorControl,
  LPCTSTR lpBinaryPathName,
  LPCTSTR lpLoadOrderGroup,
  LPDWORD lpdwTagId,
  LPCTSTR lpDependencies,
  LPCTSTR lpServiceStartName,
  LPCTSTR lpPassword
);

Parameters:

Name	Type	Description
`hSCManager`	`SC_HANDLE`	A handle to the service control manager database.
`lpServiceName`	`LPCTSTR`	The unique name of the service to be installed.
`lpDisplayName`	`LPCTSTR`	The display name for the service.
`dwDesiredAccess`	`DWORD`	Access rights for the service.
`dwServiceType`	`DWORD`	The type of service.
`dwStartType`	`DWORD`	When to start the service.
`dwErrorControl`	`DWORD`	The error control severity.
`lpBinaryPathName`	`LPCTSTR`	The fully qualified path to the service executable file.
`lpLoadOrderGroup`	`LPCTSTR`	Name of the load order group the service belongs to.
`lpdwTagId`	`LPDWORD`	Pointer to a variable that receives a unique tag value.
`lpDependencies`	`LPCTSTR`	A string that specifies an array of null-separated service names.
`lpServiceStartName`	`LPCTSTR`	The account name under which the service should run.
`lpPassword`	`LPCTSTR`	The password for the service account.

`DeleteService`

Marks a specified service for deletion from the service control manager database.

BOOL DeleteService(
  SC_HANDLE hService
);

Parameters:

Name	Type	Description
`hService`	`SC_HANDLE`	A handle to the service to be deleted.

`StartService`

Starts a service and any processes it depends on.

BOOL StartService(
  SC_HANDLE hService,
  DWORD     dwNumServiceArgs,
  LPCWSTR   *lpServiceArgVectors
);

Parameters:

Name	Type	Description
`hService`	`SC_HANDLE`	A handle to the service to be started.
`dwNumServiceArgs`	`DWORD`	The number of arguments to be passed to the service.
`lpServiceArgVectors`	`LPCWSTR *`	An array of pointers to null-terminated strings.