EnumProcessModules function (psapi.h)

Retrieves a handle for each module in the specified process.

To control whether a 64-bit application enumerates 32-bit modules, 64-bit modules, or both types of modules, use the EnumProcessModulesEx function.


BOOL EnumProcessModules(
  [in]  HANDLE  hProcess,
  [out] HMODULE *lphModule,
  [in]  DWORD   cb,
  [out] LPDWORD lpcbNeeded


[in] hProcess

A handle to the process.

[out] lphModule

An array that receives the list of module handles.

[in] cb

The size of the lphModule array, in bytes.

[out] lpcbNeeded

The number of bytes required to store all module handles in the lphModule array.

Return value

If the function succeeds, the return value is nonzero.

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


The EnumProcessModules function is primarily designed for use by debuggers and similar applications that must extract module information from another process. If the module list in the target process is corrupted or not yet initialized, or if the module list changes during the function call as a result of DLLs being loaded or unloaded, EnumProcessModules may fail or return incorrect information.

It is a good idea to specify a large array of HMODULE values, because it is hard to predict how many modules there will be in the process at the time you call EnumProcessModules. To determine if the lphModule array is too small to hold all module handles for the process, compare the value returned in lpcbNeeded with the value specified in cb. If lpcbNeeded is greater than cb, increase the size of the array and call EnumProcessModules again.

To determine how many modules were enumerated by the call to EnumProcessModules, divide the resulting value in the lpcbNeeded parameter by sizeof(HMODULE).

The EnumProcessModules function does not retrieve handles for modules that were loaded with the LOAD_LIBRARY_AS_DATAFILE or similar flags. For more information, see LoadLibraryEx.

Do not call CloseHandle on any of the handles returned by this function. The information comes from a snapshot, so there are no resources to be freed.

If this function is called from a 32-bit application running on WOW64, it can only enumerate the modules of a 32-bit process. If the process is a 64-bit process, this function fails and the last error code is ERROR_PARTIAL_COPY (299).

To take a snapshot of specified processes and the heaps, modules, and threads used by these processes, use the CreateToolhelp32Snapshot function.

Starting with Windows 7 and Windows Server 2008 R2, Psapi.h establishes version numbers for the PSAPI functions. The PSAPI version number affects the name used to call the function and the library that a program must load.

If PSAPI_VERSION is 2 or greater, this function is defined as K32EnumProcessModules in Psapi.h and exported in Kernel32.lib and Kernel32.dll. If PSAPI_VERSION is 1, this function is defined as EnumProcessModules in Psapi.h and exported in Psapi.lib and Psapi.dll as a wrapper that calls K32EnumProcessModules.

Programs that must run on earlier versions of Windows as well as Windows 7 and later versions should always call this function as EnumProcessModules. To ensure correct resolution of symbols, add Psapi.lib to the TARGETLIBS macro and compile the program with -DPSAPI_VERSION=1. To use run-time dynamic linking, load Psapi.dll.


For an example, see Enumerating All Processes or Enumerating All Modules for a Process.


Requirement Value
Minimum supported client Windows XP [desktop apps only]
Minimum supported server Windows Server 2003 [desktop apps only]
Target Platform Windows
Header psapi.h
Library Kernel32.lib on Windows 7 and Windows Server 2008 R2; Psapi.lib (if PSAPI_VERSION=1) on Windows 7 and Windows Server 2008 R2; Psapi.lib on Windows Server 2008, Windows Vista, Windows Server 2003 and Windows XP
DLL Kernel32.dll on Windows 7 and Windows Server 2008 R2; Psapi.dll (if PSAPI_VERSION=1) on Windows 7 and Windows Server 2008 R2; Psapi.dll on Windows Server 2008, Windows Vista, Windows Server 2003 and Windows XP

See also




Module Information

PSAPI Functions