MutexAcl.Create(Boolean, String, Boolean, MutexSecurity) Method

Definition

Namespace:

System.Threading

Assembly:

System.Threading.AccessControl.dll

Source:

MutexAcl.cs

Gets or creates Mutex instance, allowing a MutexSecurity to be optionally specified to set it during the mutex creation.

public:
 static System::Threading::Mutex ^ Create(bool initiallyOwned, System::String ^ name, [Runtime::InteropServices::Out] bool % createdNew, System::Security::AccessControl::MutexSecurity ^ mutexSecurity);

public static System.Threading.Mutex Create (bool initiallyOwned, string? name, out bool createdNew, System.Security.AccessControl.MutexSecurity? mutexSecurity);

static member Create : bool * string * bool * System.Security.AccessControl.MutexSecurity -> System.Threading.Mutex

Public Shared Function Create (initiallyOwned As Boolean, name As String, ByRef createdNew As Boolean, mutexSecurity As MutexSecurity) As Mutex

Parameters

initiallyOwned

Boolean

true to give the calling thread initial ownership of the named system mutex if the named system mutex is created as a result of this call; otherwise, false.

name

String

The name, if the synchronization object is to be shared with other processes; otherwise, null or an empty string. The name is case-sensitive. The backslash character (\) is reserved and may only be used to specify a namespace. For more information on namespaces, see the remarks section. There may be further restrictions on the name depending on the operating system. For example, on Unix-based operating systems, the name after excluding the namespace must be a valid file name.

createdNew

Boolean

When this method returns, this argument is always set to true if a local mutex is created; that is, when name is null or Empty. If name has a valid non-empty value, this argument is set to true when the system mutex is created, or it is set to false if an existing system mutex is found with that name. This parameter is passed uninitialized.

mutexSecurity

MutexSecurity

The optional mutex access control security to apply.

Returns

Mutex

An object that represents a system mutex, if named, or a local mutex, if nameless.

Exceptions

ArgumentException

.NET Framework only: name is longer than MAX_PATH (260 characters).

IOException

name is invalid. This can be for various reasons, including some restrictions that may be placed by the operating system, such as an unknown prefix or invalid characters. Note that the name and common prefixes "Global\" and "Local\" are case-sensitive.

-or-

There was some other error. The HResult property may provide more information.

DirectoryNotFoundException

Windows only: name specified an unknown namespace. See Object Names for more information.

PathTooLongException

The name is too long. Length restrictions may depend on the operating system or configuration.

WaitHandleCannotBeOpenedException

A synchronization object with the provided name cannot be created. A synchronization object of a different type might have the same name.

Remarks

The name may be prefixed with Global\ or Local\ to specify a namespace. When the Global namespace is specified, the synchronization object may be shared with any processes on the system. When the Local namespace is specified, which is also the default when no namespace is specified, the synchronization object may be shared with processes in the same session. On Windows, a session is a login session, and services typically run in a different non-interactive session. On Unix-like operating systems, each shell has its own session. Session-local synchronization objects may be appropriate for synchronizing between processes with a parent/child relationship where they all run in the same session. For more information about synchronization object names on Windows, see Object Names.

If a name is provided and a synchronization object of the requested type already exists in the namespace, the existing synchronization object is opened. If a synchronization object of a different type already exists in the namespace, a WaitHandleCannotBeOpenedException is thrown. Otherwise, a new synchronization object is created.

Caution

By default, a named mutex is not restricted to the user that created it. Other users may be able to open and use the mutex, including interfering with the mutex by entering the mutex and not exiting it. To restrict access to specific users, you can pass in a MutexSecurity when creating the named mutex. Avoid using named mutexes without access restrictions on systems that might have untrusted users running code.