FreeLibrary

FreeLibrary，計算機語言。意思是釋放指定的動態程式庫。

基本介紹

• 外文名：FreeLibrary
• 說明：釋放指定的動態程式庫
• 返回值：Long
• 說明：hLibModule Long

VB

VB聲明

Declare Function FreeLibrary Lib "kernel32" Alias "FreeLibrary" (ByVal hLibModule As Long) As Long

說明

釋放指定的動態程式庫，它們早先是用LoadLibrary API函式裝載的

返回值

Long，非零表示成功，零表示失敗。會設定GetLastError

參數表

參數 類型及說明

hLibModule Long，要釋放的一個庫句柄

在VB里使用

只能用這個函式釋放那些由應用程式明確裝載的DLL。對LoadLibrary的每一次調用都應該有一個對應的FreeLibrary調用

delphi聲明

function FreeLibrary; external kernel32 name 'FreeLibrary';

C++

Frees the loaded dynamic-link library (DLL) module and, if necessary, decrements its reference count. When the reference count reaches zero, the module is unloaded from the address space of the calling process and the handle is no longer valid.

Syntax

C++

BOOL WINAPI FreeLibrary( _In_ HMODULE hModule);

Parameters

hModule [in]A handle to the loaded library module. The LoadLibrary, LoadLibraryEx, GetModuleHandle, or GetModuleHandleEx function returns this handle.

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 the GetLastError function.

Remarks

The system maintains a per-process reference count for each loaded module. A module that was loaded at process initialization due to load-time dynamic linking has a reference count of one. The reference count for a module is incremented each time the module is loaded by a call to LoadLibrary. The reference count is also incremented by a call to LoadLibraryEx unless the module is being loaded for the first time and is being loaded as a data or image file.

The reference count is decremented each time the FreeLibrary or FreeLibraryAndExitThread function is called for the module. When a module's reference count reaches zero or the process terminates, the system unloads the module from the address space of the process. Before unloading a library module, the system enables the module to detach from the process by calling the module's DllMain function, if it has one, with the DLL_PROCESS_DETACH value. Doing so gives the library module an opportunity to clean up resources allocated on behalf of the current process. After the entry-point function returns, the library module is removed from the address space of the current process.

It is not safe to call FreeLibrary from DllMain. For more information, see the Remarks section in DllMain.

Calling FreeLibrary does not affect other processes that are using the same module.

Use caution when calling FreeLibrary with a handle returned by GetModuleHandle. The GetModuleHandle function does not increment a module's reference count, so passing this handle to FreeLibrary can cause a module to be unloaded prematurely.

A thread that must unload the DLL in which it is executing and then terminate itself should call FreeLibraryAndExitThread instead of calling FreeLibrary and ExitThread separately. Otherwise, a race condition can occur. For details, see the Remarks section of FreeLibraryAndExitThread.

Windows Phone 8: This API is supported.

Examples

For an example, see Using Run-Time Dynamic Linking.

Requirements

Minimum supported client	Windows XP [desktop apps | Windows Store apps]
Minimum supported server	Windows Server 2003 [desktop apps | Windows Store apps]
Header	Winbase.h (include Windows.h)
Library	Kernel32.lib
DLL	Kernel32.dll

See also

DllMainDynamic-Link Library FunctionsFreeLibraryAndExitThreadGetModuleHandleGetModuleHandleExLoadLibraryRun-Time Dynamic Linking