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Overview |
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Group |
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Quick Info
Windows NT
| Yes
| Win95
| No
| Win32s
| No
| Import Library
| advapi32.lib
| Header File
| winsvc.h
| Unicode
| No
| Platform Notes
| None
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LockServiceDatabase
The LockServiceDatabase function locks a specified database.
SC_LOCK LockServiceDatabase(
SC_HANDLE hSCManager
| // handle of service control manager database
| );
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Parameters
hSCManager
Identifies the service control manager database. The OpenSCManager function returns this handle, which must have SC_MANAGER_LOCK access.
Return Values
If the function succeeds, the return value is a lock to the specified service
control manager database.
If the function fails, the return value is NULL. To get extended error
information, call GetLastError.
Errors
The following error code may be set by the service control manager. Other
error codes may be set by registry functions that are called by the service control
manager.
Value
| Meaning
| ERROR_ACCESS_DENIED
| The specified handle was not opened with SC_MANAGER_LOCK access.
| ERROR_INVALID_HANDLE
| The specified handle is invalid.
| ERROR_SERVICE_DATABASE_LOCKED
| The database is locked.
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Remarks
The LockServiceDatabase function tries to acquire a lock on the specified database. Only one process
at a time can have a lock on a database.
A lock is a protocol used by setup and configuration programs and the service
control manager to serialize access to the service tree in the registry. The
only time the service control manager acquires a lock is when it is starting a
service. Setup and configuration programs are expected to acquire a lock before
using the ChangeServiceConfig or SetServiceObjectSecurity function to reconfigure a service. They should also acquire a lock before
using the registry functions to reconfigure a service. The lock prevents the
service control manager from starting a service while it is being reconfigured.
A call to the StartService function to start a service in a locked database fails. All other service
control manager functions are not affected by a lock.
The lock is held until the SC_LOCK handle is specified in a subsequent call to
the UnlockServiceDatabase function. If a process that is holding a lock terminates, the service control
manager automatically cleans up and releases the lock.
See Also
ChangeServiceConfig, OpenSCManager, QueryServiceLockStatus, SetServiceObjectSecurity, StartService, UnlockServiceDatabase
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Unix Manual Pages
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