OpenProcess

The OpenProcess function returns a handle to an existing process object.

HANDLE OpenProcess(
  DWORD dwDesiredAccess,  // access flag
  BOOL bInheritHandle,    // handle inheritance flag
  DWORD dwProcessId       // process identifier
);
 

Parameters

dwDesiredAccess

Specifies the access to the process object. For operating systems that support security checking, this access is checked against any security descriptor for the target process. Any combination of the following access flags can be specified in addition to the STANDARD_RIGHTS_REQUIRED access flags:

Access	Description
PROCESS_ALL_ACCESS	Specifies all possible access flags for the process object.
PROCESS_CREATE_PROCESS	Used internally.
PROCESS_CREATE_THREAD	Enables using the process handle in the CreateRemoteThread function to create a thread in the process.
PROCESS_DUP_HANDLE	Enables using the process handle as either the source or target process in the DuplicateHandle function to duplicate a handle.
PROCESS_QUERY_INFORMATION	Enables using the process handle in the GetExitCodeProcess and GetPriorityClass functions to read information from the process object.
PROCESS_SET_INFORMATION	Enables using the process handle in the SetPriorityClass function to set the priority class of the process.
PROCESS_TERMINATE	Enables using the process handle in the TerminateProcess function to terminate the process.
PROCESS_VM_OPERATION	Enables using the process handle in the VirtualProtectEx and WriteProcessMemory functions to modify the virtual memory of the process.
PROCESS_VM_READ	Enables using the process handle in the ReadProcessMemory function to read from the virtual memory of the process.
PROCESS_VM_WRITE	Enables using the process handle in the WriteProcessMemory function to write to the virtual memory of the process.
SYNCHRONIZE	Windows NT: Enables using the process handle in any of the wait functions to wait for the process to terminate.

bInheritHandle

Specifies whether the returned handle can be inherited by a new process created by the current process. If TRUE, the handle is inheritable.

dwProcessId

Specifies the process identifier of the process to open.

Return Values

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

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.

QuickInfo

  Windows NT: Requires version 3.1 or later.
  Windows: Requires Windows 95 or later.
  Windows CE: Unsupported.
  Header: Declared in winbase.h.
  Import Library: Use kernel32.lib.

See Also

Processes and Threads Overview, Process and Thread Functions, CloseHandle, CreateProcess, CreateRemoteThread, DuplicateHandle, GetCurrentProcess, GetCurrentProcessId, GetExitCodeProcess, GetPriorityClass, ReadProcessMemory, SetPriorityClass, TerminateProcess, VirtualProtectEx, WriteProcessMemory