GetModuleHandleExA function (libloaderapi.h)

Retrieves a module handle for the specified module and increments the module's reference count unless GET_MODULE_HANDLE_EX_FLAG_UNCHANGED_REFCOUNT is specified. The module must have been loaded by the calling process.

Syntax

BOOL GetModuleHandleExA(
  [in]           DWORD   dwFlags,
  [in, optional] LPCSTR  lpModuleName,
  [out]          HMODULE *phModule
);

Parameters

[in] dwFlags

This parameter can be zero or one or more of the following values. If the module's reference count is incremented, the caller must use the FreeLibrary function to decrement the reference count when the module handle is no longer needed.

GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS (0x00000004)

The lpModuleName parameter is an address in the module.

GET_MODULE_HANDLE_EX_FLAG_PIN (0x00000001)

The module stays loaded until the process is terminated, no matter how many times FreeLibrary is called.

This option cannot be used with GET_MODULE_HANDLE_EX_FLAG_UNCHANGED_REFCOUNT.

GET_MODULE_HANDLE_EX_FLAG_UNCHANGED_REFCOUNT (0x00000002)

The reference count for the module is not incremented. This option is equivalent to the behavior of GetModuleHandle. Do not pass the retrieved module handle to the FreeLibrary function; doing so can cause the DLL to be unmapped prematurely. For more information, see Remarks.

This option cannot be used with GET_MODULE_HANDLE_EX_FLAG_PIN.

[in, optional] lpModuleName

The name of the loaded module (either a .dll or .exe file), or an address in the module (if dwFlags is GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS).

For a module name, if the file name extension is omitted, the default library extension .dll is appended. The file name string can include a trailing point character (.) to indicate that the module name has no extension. The string does not have to specify a path. When specifying a path, be sure to use backslashes (\), not forward slashes (/). The name is compared (case independently) to the names of modules currently mapped into the address space of the calling process.

If this parameter is NULL, the function returns a handle to the file used to create the calling process (.exe file).

[out] phModule

A handle to the specified module. If the function fails, this parameter is NULL.

The GetModuleHandleEx function does not retrieve handles for modules that were loaded using the LOAD_LIBRARY_AS_DATAFILE flag. For more information, see LoadLibraryEx.

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, see GetLastError.

Remarks

The handle returned is not global or inheritable. It cannot be duplicated or used by another process.

If lpModuleName does not include a path and there is more than one loaded module with the same base name and extension, you cannot predict which module handle will be returned. To work around this problem, you could specify a path, use side-by-side assemblies, or specify a memory location rather than a DLL name in the lpModuleName parameter.

If dwFlags contains GET_MODULE_HANDLE_EX_FLAG_UNCHANGED_REFCOUNT, the GetModuleHandleEx function returns a handle to a mapped module without incrementing its reference count. However, if this handle is passed to the FreeLibrary function, the reference count of the mapped module will be decremented. Therefore, do not pass a handle returned by GetModuleHandleEx with GET_MODULE_HANDLE_EX_FLAG_UNCHANGED_REFCOUNT to the FreeLibrary function. Doing so can cause a DLL module to be unmapped prematurely.

If dwFlags contains GET_MODULE_HANDLE_EX_FLAG_UNCHANGED_REFCOUNT, this function must be used carefully in a multithreaded application. There is no guarantee that the module handle remains valid between the time this function returns the handle and the time it is used. For example, a thread retrieves a module handle, but before it uses the handle, a second thread frees the module. If the system loads another module, it could reuse the module handle that was recently freed. Therefore, first thread would have a handle to a module different than the one intended.

To compile an application that uses this function, define _WIN32_WINNT as 0x0501 or later. For more information, see Using the Windows Headers.

Requirements

See also

Dynamic-Link Library Functions

FreeLibrary

GetModuleFileName

LoadLibrary

LoadLibraryEx