CreateToolhelp32Snapshot

A version of this page is also available for

Windows Embedded CE 6.0 R3

4/8/2010

This function takes a snapshot of the processes, heaps, modules, and threads used by the processes.

Syntax

HANDLE WINAPI CreateToolhelp32Snapshot(
  DWORD dwFlags,
  DWORD th32ProcessID
);

Parameters

• dwFlags
  [in] Portions of the system to include in the snapshot. The following table shows possible values.

  Value	Description
  TH32CS_GETALLMODS	Includes all modules in the snapshot. Must be used with the OR operator in combination with TH32CS_SNAPMODULE.
  TH32CS_SNAPALL	Equivalent to specifying TH32CS_SNAPHEAPLIST, TH32CS_SNAPMODULE, TH32CS_SNAPPROCESS, and TH32CS_SNAPTHREAD.
  TH32CS_SNAPHEAPLIST	Includes the heap list of the specified process in the snapshot.
  TH32CS_SNAPMODULE	Includes the module list of the specified process in the snapshot.
  TH32CS_SNAPNOHEAPS	By default, the process heap information is included when creating PROCESS snapshot. For a more efficient way of receiving the basic information of the process, use this flag with TH32CS_SNAPPROCESS.
  TH32CS_SNAPPROCESS	Includes the process list in the snapshot.
  TH32CS_SNAPTHREAD	Includes the thread list in the snapshot.

• th32ProcessID
  [in] Process identifier. This parameter can be zero to indicate the current process. This parameter is used when TH32CS_SNAPHEAPLIST or TH32CS_SNAPMODULE is specified. Otherwise, it is ignored.

Return Value

An open handle to the specified snapshot indicates success. INVALID_HANDLE_VALUE indicates failure.

Remarks

The snapshot returned is a copy of the current state of the system. To close a snapshot, call the CloseToolhelp32Snapshot function. Do not call the CloseHandle function to close the snapshot call. That generates a memory leak. The snapshot taken by this function is examined by other tool help functions to provide their results. Access to the snapshot is read-only.

The snapshot handle acts like an object handle and is subject to the same rules regarding the processes and threads where it is valid. To retrieve an extended error status code generated by this function, use the GetLastError function. Because the data captured by CreateToolhelp32Snapshot is static and the system is dynamic, use try-excepts around the APIs that access this data.

Requirements

See Also

Reference

ToolHelp Functions
CloseToolhelp32Snapshot
Process32First
Process32Next

Other Resources

CloseHandle