OpenProcess function

Opens an existing local process object.

Syntax

HANDLE OpenProcess(
  DWORD dwDesiredAccess,
  BOOL  bInheritHandle,
  DWORD dwProcessId
);

Parameters

dwDesiredAccess

The access to the process object. This access right is checked against the security descriptor for the process. This parameter can be one or more of the process access rights.

If the caller has enabled the SeDebugPrivilege privilege, the requested access is granted regardless of the contents of the security descriptor.

bInheritHandle

If this value is TRUE, processes created by this process will inherit the handle. Otherwise, the processes do not inherit this handle.

dwProcessId

The identifier of the local process to be opened.

If the specified process is the System Process (0x00000000), the function fails and the last error code is ERROR_INVALID_PARAMETER. If the specified process is the Idle process or one of the CSRSS processes, this function fails and the last error code is ERROR_ACCESS_DENIED because their access restrictions prevent user-level code from opening them.

If you are using GetCurrentProcessId as an argument to this function, consider using GetCurrentProcess instead of OpenProcess, for improved performance.

Return Value

If the function succeeds, the return value is an open handle to the specified process.

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

Remarks

To open a handle to another local process and obtain full access rights, you must enable the SeDebugPrivilege privilege. For more information, see Changing Privileges in a Token.

The handle returned by the OpenProcess function can be used in any function that requires a handle to a process, such as the wait functions, provided the appropriate access rights were requested.

When you are finished with the handle, be sure to close it using the CloseHandle function.

Examples

For an example, see Taking a Snapshot and Viewing Processes.

Requirements

   
Minimum supported client Windows XP [desktop apps | UWP apps]
Minimum supported server Windows Server 2003 [desktop apps | UWP apps]
Target Platform Windows
Header processthreadsapi.h (include Windows Server 2003, Windows Vista, Windows 7, Windows Server 2008 Windows Server 2008 R2, Windows.h)
Library Kernel32.lib
DLL Kernel32.dll

See Also

AssignProcessToJobObject

CloseHandle

CreateProcess

CreateRemoteThread

DuplicateHandle

GetCurrentProcess

GetCurrentProcessId

GetExitCodeProcess

GetModuleFileNameEx

GetPriorityClass

Process and Thread Functions

Processes

ReadProcessMemory

SetPriorityClass

SetProcessWorkingSetSize

TerminateProcess

VirtualProtectEx

WriteProcessMemory