LoadLibrary加载dll 返回NULL，GetLastError＝126

cokomowang 2016-02-15 11:36:18

大家新年好- -刚刚过完年又要开始调程序码代码了

如题，但是情况有点复杂

两个不同的工程，工程a和工程b，我自己在工程c中写了一个c.dll来给工程a和b调用，c.dll还依赖另外两个dll，一共三个dll都全部放到了两个工程的exe目录下

但是，在工程a中调用c.dll的函数成功；而在工程b中则无法成功加载，GetLastError＝126。
可以肯定工程b的dll路径是绝对没有问题的，原因是我另外写了一个测试用的，不依赖任何其他dll 的一个dll（其中的函数只有return语句），在a和b中都被成功调用

我觉得问题还是出在c.dll缺少依赖上，但是不明白为何两个工程一个可以另一个不行，求解答啊TT

dependency walker打开c.dll的部分缺失项如下：



API-MS-WIN-CORE-APIQUERY-L1-1-0.DLL

API-MS-WIN-CORE-APPCOMPAT-L1-1-1.DLL

API-MS-WIN-CORE-APPINIT-L1-1-0.DLL

API-MS-WIN-CORE-ATOMS-L1-1-0.DLL

API-MS-WIN-CORE-COM-L1-1-0

API-MS-WIN-CORE-COM-L1-1-1.DLL

API-MS-WIN-CORE-COM-MIDLPROXYSTUB-L1-1-0.DLL

API-MS-WIN-CORE-COM-PRIVATE-L1-1-0.DLL

API-MS-WIN-CORE-COM-PRIVATE-L1-1-1.DLL

API-MS-WIN-CORE-COMM-L1-1-0.DLL

API-MS-WIN-CORE-CONSOLE-L1-1-0.DLL

API-MS-WIN-CORE-CONSOLE-L2-1-0.DLL

API-MS-WIN-CORE-CRT-L1-1-0.DLL

API-MS-WIN-CORE-CRT-L2-1-0.DLL

API-MS-WIN-CORE-DATETIME-L1-1-1.DLL

API-MS-WIN-CORE-DATETIME-L1-1-2.DLL

API-MS-WIN-CORE-DEBUG-L1-1-1.DLL

API-MS-WIN-CORE-DELAYLOAD-L1-1-1.DLL

API-MS-WIN-CORE-ENCLAVE-L1-1-0.DLL

API-MS-WIN-CORE-ERRORHANDLING-L1-1-1.DLL

API-MS-WIN-CORE-ERRORHANDLING-L1-1-3.DLL

API-MS-WIN-CORE-FIBERS-L1-1-1.DLL

API-MS-WIN-CORE-FIBERS-L2-1-1.DLL

API-MS-WIN-CORE-FILE-L1-2-1.DLL

API-MS-WIN-CORE-FILE-L1-2-2.DLL

API-MS-WIN-CORE-FILE-L2-1-1.DLL

API-MS-WIN-CORE-FILE-L2-1-2.DLL

API-MS-WIN-CORE-HANDLE-L1-1-0.DLL

API-MS-WIN-CORE-HEAP-L1-2-0.DLL

API-MS-WIN-CORE-HEAP-L2-1-0.DLL

API-MS-WIN-CORE-HEAP-OBSOLETE-L1-1-0.DLL

API-MS-WIN-CORE-INTERLOCKED-L1-2-0.DLL

API-MS-WIN-CORE-IO-L1-1-1.DLL

API-MS-WIN-CORE-JOB-L1-1-0.DLL

API-MS-WIN-CORE-JOB-L2-1-0.DLL

API-MS-WIN-CORE-KERNEL32-LEGACY-L1-1-1.DLL

API-MS-WIN-CORE-KERNEL32-LEGACY-L1-1-4.DLL

API-MS-WIN-CORE-KERNEL32-PRIVATE-L1-1-1.DLL

API-MS-WIN-CORE-KERNEL32-PRIVATE-L1-1-2.DLL

API-MS-WIN-CORE-LIBRARYLOADER-L1-2-0.DLL

API-MS-WIN-CORE-LIBRARYLOADER-L1-2-1.DLL

API-MS-WIN-CORE-LIBRARYLOADER-L2-1-0.DLL

API-MS-WIN-CORE-LOCALIZATION-L1-2-1.DLL

API-MS-WIN-CORE-LOCALIZATION-L1-2-2.DLL

API-MS-WIN-CORE-LOCALIZATION-L2-1-0.DLL

API-MS-WIN-CORE-LOCALIZATION-OBSOLETE-L1-3-0.DLL

API-MS-WIN-CORE-LOCALIZATION-PRIVATE-L1-1-0.DLL

API-MS-WIN-CORE-MEMORY-L1-1-2.DLL

API-MS-WIN-CORE-NAMEDPIPE-L1-2-0.DLL

API-MS-WIN-CORE-NAMEDPIPE-L1-2-2.DLL

API-MS-WIN-CORE-NAMESPACE-L1-1-0.DLL

API-MS-WIN-CORE-NORMALIZATION-L1-1-0.DLL

API-MS-WIN-CORE-PATH-L1-1-0.DLL

API-MS-WIN-CORE-PRIVATEPROFILE-L1-1-1.DLL

API-MS-WIN-CORE-PROCESSENVIRONMENT-L1-2-0.DLL

API-MS-WIN-CORE-PROCESSSNAPSHOT-L1-1-0.DLL

API-MS-WIN-CORE-PROCESSTHREADS-L1-1-1

API-MS-WIN-CORE-PROCESSTHREADS-L1-1-2.DLL

API-MS-WIN-CORE-PROCESSTHREADS-L1-1-3.DLL

API-MS-WIN-CORE-PROCESSTOPOLOGY-L1-2-0.DLL

API-MS-WIN-CORE-PROFILE-L1-1-0.DLL

API-MS-WIN-CORE-PSAPI-ANSI-L1-1-0.DLL

API-MS-WIN-CORE-PSAPI-L1-1-0.DLL

API-MS-WIN-CORE-PSM-KEY-L1-1-0.DLL

API-MS-WIN-CORE-QUIRKS-L1-1-0.DLL

API-MS-WIN-CORE-REALTIME-L1-1-0.DLL

API-MS-WIN-CORE-REGISTRY-L1-1-0.DLL

API-MS-WIN-CORE-REGISTRY-L1-1-1.DLL

API-MS-WIN-CORE-REGISTRYUSERSPECIFIC-L1-1-0.DLL

API-MS-WIN-CORE-RTLSUPPORT-L1-2-0.DLL

API-MS-WIN-CORE-SHLWAPI-LEGACY-L1-1-0.DLL

API-MS-WIN-CORE-SHLWAPI-OBSOLETE-L1-2-0.DLL

API-MS-WIN-CORE-SIDEBYSIDE-L1-1-0.DLL

API-MS-WIN-CORE-STRING-L1-1-0.DLL

API-MS-WIN-CORE-STRING-L2-1-0.DLL

API-MS-WIN-CORE-STRING-L2-1-1.DLL

API-MS-WIN-CORE-STRING-OBSOLETE-L1-1-0.DLL

API-MS-WIN-CORE-STRINGANSI-L1-1-0.DLL

API-MS-WIN-CORE-SYNCH-L1-1-0.DLL

API-MS-WIN-CORE-SYNCH-L1-2-0.DLL

API-MS-WIN-CORE-SYNCH-L1-2-1.DLL

API-MS-WIN-CORE-SYSINFO-L1-2-1.DLL

API-MS-WIN-CORE-SYSINFO-L1-2-3.DLL

API-MS-WIN-CORE-SYSTEMTOPOLOGY-L1-1-0.DLL

API-MS-WIN-CORE-THREADPOOL-L1-2-0.DLL

API-MS-WIN-CORE-THREADPOOL-LEGACY-L1-1-0.DLL

API-MS-WIN-CORE-THREADPOOL-PRIVATE-L1-1-0.DLL

API-MS-WIN-CORE-TIMEZONE-L1-1-0.DLL

API-MS-WIN-CORE-URL-L1-1-0.DLL

API-MS-WIN-CORE-UTIL-L1-1-0.DLL

API-MS-WIN-CORE-VERSION-L1-1-0.DLL

API-MS-WIN-CORE-VERSION-L1-1-1.DLL

API-MS-WIN-CORE-VERSION-PRIVATE-L1-1-0.DLL

API-MS-WIN-CORE-VERSIONANSI-L1-1-0.DLL

API-MS-WIN-CORE-VERSIONANSI-L1-1-1.DLL

API-MS-WIN-CORE-WINDOWSERRORREPORTING-L1-1-0.DLL

API-MS-WIN-CORE-WINRT-ERROR-L1-1-1.DLL

API-MS-WIN-CORE-WINRT-STRING-L1-1-0.DLL

API-MS-WIN-CORE-WOW64-L1-1-0.DLL

API-MS-WIN-CORE-WOW64-L1-1-1.DLL

API-MS-WIN-CORE-XSTATE-L2-1-0.DLL

API-MS-WIN-DEVICES-CONFIG-L1-1-1.DLL

API-MS-WIN-EVENTING-CLASSICPROVIDER-L1-1-0.DLL

API-MS-WIN-EVENTING-PROVIDER-L1-1-0.DLL

API-MS-WIN-MM-JOYSTICK-L1-1-0.DLL

API-MS-WIN-MM-MISC-L1-1-1.DLL

API-MS-WIN-MM-MME-L1-1-0.DLL

API-MS-WIN-MM-TIME-L1-1-0.DLL

API-MS-WIN-SECURITY-APPCONTAINER-L1-1-0.DLL

API-MS-WIN-SECURITY-BASE-L1-2-0.DLL

API-MS-WIN-SECURITY-LSALOOKUP-L1-1-1.DLL

API-MS-WIN-SECURITY-LSAPOLICY-L1-1-0.DLL

API-MS-WIN-SECURITY-SDDL-L1-1-0.DLL

API-MS-WIN-SERVICE-MANAGEMENT-L1-1-0.DLL

API-MS-WIN-SERVICE-WINSVC-L1-2-0.DLL

API-MS-WIN-SHELL-SHELLCOM-L1-1-0.DLL

API-MS-WIN-SHELL-SHELLFOLDERS-L1-1-0.DLL

API-MS-WIN-STORAGE-EXPORTS-EXTERNAL-L1-1-0.DLL

API-MS-WIN-STORAGE-EXPORTS-INTERNAL-L1-1-0.DLL

SDL2_MIXER.DLL

API-MS-WIN-APPMODEL-IDENTITY-L1-2-0.DLL

API-MS-WIN-APPMODEL-RUNTIME-INTERNAL-L1-1-0.DLL

API-MS-WIN-APPMODEL-RUNTIME-L1-1-0.DLL

API-MS-WIN-APPMODEL-RUNTIME-L1-1-1.DLL

API-MS-WIN-APPMODEL-STATE-L1-2-0.DLL

API-MS-WIN-APPMODEL-UNLOCK-L1-1-0.DLL

API-MS-WIN-BASE-UTIL-L1-1-0.DLL

API-MS-WIN-CORE-CALENDAR-L1-1-0.DLL

API-MS-WIN-CORE-COM-L2-1-1.DLL

API-MS-WIN-CORE-DEBUG-L1-1-0.DLL

API-MS-WIN-CORE-DELAYLOAD-L1-1-0.DLL

API-MS-WIN-CORE-ERRORHANDLING-L1-1-0.DLL

API-MS-WIN-CORE-FIBERS-L1-1-0.DLL

API-MS-WIN-CORE-FILE-L1-1-0.DLL

API-MS-WIN-CORE-FILE-L1-2-0.DLL

API-MS-WIN-CORE-FILE-L2-1-0.DLL

API-MS-WIN-CORE-HEAP-L1-1-0.DLL

API-MS-WIN-CORE-INTERLOCKED-L1-1-0.DLL

API-MS-WIN-CORE-IO-L1-1-0.DLL

API-MS-WIN-CORE-KERNEL32-LEGACY-L1-1-0.DLL

API-MS-WIN-CORE-LIBRARYLOADER-L1-1-0.DLL

API-MS-WIN-CORE-LOCALIZATION-L1-1-0.DLL

API-MS-WIN-CORE-LOCALIZATION-L1-2-0.DLL

API-MS-WIN-CORE-LOCALIZATION-OBSOLETE-L1-2-0.DLL

API-MS-WIN-CORE-LOCALREGISTRY-L1-1-0.DLL

API-MS-WIN-CORE-MARSHAL-L1-1-0.DLL

API-MS-WIN-CORE-MEMORY-L1-1-0.DLL

API-MS-WIN-CORE-MISC-L1-1-0.DLL

API-MS-WIN-CORE-PERFCOUNTERS-L1-1-0.DLL

API-MS-WIN-CORE-PROCESSENVIRONMENT-L1-1-0.DLL

API-MS-WIN-CORE-PROCESSTHREADS-L1-1-0.DLL

API-MS-WIN-CORE-PROCESSTHREADS-L1-1-1.DLL

API-MS-WIN-CORE-PROCESSTOPOLOGY-OBSOLETE-L1-1-0.DLL

API-MS-WIN-CORE-PSM-APPNOTIFY-L1-1-0.DLL

API-MS-WIN-CORE-REALTIME-L1-1-1.DLL

API-MS-WIN-CORE-REGISTRY-L2-2-0.DLL

API-MS-WIN-CORE-REGISTRY-PRIVATE-L1-1-0.DLL

API-MS-WIN-CORE-RTLSUPPORT-L1-1-0.DLL

API-MS-WIN-CORE-SHUTDOWN-L1-1-1.DLL

API-MS-WIN-CORE-SYSINFO-L1-1-0.DLL

API-MS-WIN-CORE-SYSINFO-L1-2-0.DLL

API-MS-WIN-CORE-TOOLHELP-L1-1-0.DLL

API-MS-WIN-CORE-WINRT-ERRORPRIVATE-L1-1-1.DLL

API-MS-WIN-CORE-WINRT-L1-1-0.DLL

API-MS-WIN-CORE-WINRT-PROPERTYSETPRIVATE-L1-1-0.DLL

API-MS-WIN-CORE-WINRT-PROPERTYSETPRIVATE-L1-1-1.DLL

API-MS-WIN-CORE-WINRT-REGISTRATION-L1-1-0.DLL

API-MS-WIN-CORE-WINRT-ROBUFFER-L1-1-0.DLL

API-MS-WIN-COREUI-SECRUNTIME-L1-1-0.DLL

API-MS-WIN-CRT-LOCALE-L1-1-0.DLL

API-MS-WIN-CRT-PRIVATE-L1-1-0.DLL

API-MS-WIN-CRT-RUNTIME-L1-1-0.DLL

API-MS-WIN-CRT-STRING-L1-1-0.DLL

API-MS-WIN-CRT-TIME-L1-1-0.DLL

API-MS-WIN-DEVICES-QUERY-L1-1-1.DLL

API-MS-WIN-DOWNLEVEL-ADVAPI32-L1-1-0.DLL

API-MS-WIN-DOWNLEVEL-ADVAPI32-L2-1-0.DLL

API-MS-WIN-DOWNLEVEL-KERNEL32-L2-1-0.DLL

API-MS-WIN-DOWNLEVEL-NORMALIZ-L1-1-0.DLL

API-MS-WIN-DOWNLEVEL-OLE32-L1-1-0.DLL

API-MS-WIN-DOWNLEVEL-SHELL32-L1-1-0.DLL

API-MS-WIN-DOWNLEVEL-SHLWAPI-L1-1-0.DLL

API-MS-WIN-DOWNLEVEL-SHLWAPI-L2-1-0.DLL

。。。。。。。。。

a.cpp



#include <stdio.h>

#include <Windows.h>

#include <tchar.h>



int main()

{

	HMODULE hModule = NULL;

	typedef int(*Func)();



	hModule = LoadLibrary(_TEXT("..\\x64\\Release\\nMidiPlayer.dll"));

	DWORD dw = GetLastError();

	printf("%d\n", dw);



	if (hModule){



		Func fAdd = (Func)GetProcAddress(hModule, "MidiPlayerInit");

		Func fAdd2 = (Func)GetProcAddress(hModule, "MidiPlayerRun");



		printf("%d\n", fAdd());



		printf("%d\n", fAdd2());

	}

	else{

		printf("%d\n", -1);

	}



	system("pause");



	return 0;

}

b.cpp

// Fill out your copyright notice in the Description page of Project Settings.

#include "ppp.h"

#include "MyActor.h"

#include <stdio.h>

#include <Windows.h>

#include <tchar.h>





// Sets default values

AMyActor::AMyActor()

{

	// Set this actor to call Tick() every frame.  You can turn this off to improve performance if you don't need it.

	PrimaryActorTick.bCanEverTick = true;



}



void AMyActor::test()

{





}



void AMyActor::MidiPlayerInit()

{

	HMODULE hModule = NULL;

	typedef int(*Func)();



	hModule = LoadLibrary(_TEXT("..\\..\\Plugins\\MyDLL\\nMidiPlayer.dll"));



	int32 dw = GetLastError();

	UE_LOG(LogTemp, Warning, TEXT("GetLastError info = %d"), dw);



	Func fAdd = (Func)GetProcAddress(hModule, "MidiPlayerInit");

	return;

}



void AMyActor::MidiPlayerRun()

{

	HMODULE hModule = NULL;

	typedef int(*Func)();



	hModule = LoadLibrary(_TEXT("..\\..\\Plugins\\MyDLL\\nMidiPlayer.dll"));



	int32 dw = GetLastError();

	UE_LOG(LogTemp, Warning, TEXT("GetLastError info = %d"), dw);



	Func fAdd = (Func)GetProcAddress(hModule, "MidiPlayerRun");

	return;

}



// Called when the game starts or when spawned

void AMyActor::BeginPlay()

{

	Super::BeginPlay();



}



// Called every frame

void AMyActor::Tick(float DeltaTime)

{

	Super::Tick(DeltaTime);



}

...全文

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赵4老师 2016-02-19

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搜“dll hell”

cokomowang 2016-02-19

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可还是有个问题，我的工程a在没加入缺失的那一部分dll 的情况下，仍然自始至终可以调用成功，然而工程b却非得加入那一部分dll才可以。。。并不是很明白- -
如图这是a，b的两个目录

我怀疑可能是包含和库路径相关的问题？？？
这是a，b的两个路径设置，但是他们的包含路径和库路径都是未修改的
其中b 工程是UE4定制的，只有这一页是路径设置

a的

b的

cokomowang 2016-02-19

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引用 5 楼 zhoujielunzhimi 的回复:

模块路径错误。通过VS运行和直接双击exe运行时，程序当前目录不一样，那么，你的c.dll的相对路径也不一样。先试试绝对路径，看看是否成功？

引用 6 楼 CharlesSimonyi 的回复:

建议全部改成绝对路径进行一次测试以排除路径问题，相对路径容易受CurrentDirectory影响，如楼上所说，通过VS运行和直接双击exe运行时，由于CurrentDirectory的不同，像..\\..\\Plugins\\MyDLL\\nMidiPlayer.dll这样的相对路径意义是不同的，被调用的DLL的CurrentDirectory也会受宿主进程的影响而改变。

使用绝对路径后，通过vs运行和直接双击exe运行结果不一样的问题解决了，都调用dll 成功。这个问题就是相对路径引起的。不过还有另一个问题没解决——工程b 中调用dll还是不成功，我再次排查依赖项的问题，最终解决。方法是将所引用的dll的所有配套的其他dll一起放入exe目录。工程b中调用成功。

赵4老师 2016-02-16

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将除系统dll外的其它dll全部放在和exe相同目录下。

encoderlee 版主 2016-02-16

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建议全部改成绝对路径进行一次测试以排除路径问题，相对路径容易受CurrentDirectory影响，如楼上所说，通过VS运行和直接双击exe运行时，由于CurrentDirectory的不同，像..\\..\\Plugins\\MyDLL\\nMidiPlayer.dll这样的相对路径意义是不同的，被调用的DLL的CurrentDirectory也会受宿主进程的影响而改变。

sumos 2016-02-16

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模块路径错误。通过VS运行和直接双击exe运行时，程序当前目录不一样，那么，你的c.dll的相对路径也不一样。先试试绝对路径，看看是否成功？

fefe82 2016-02-15

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在使用 GetLastError 之前，必须先确认真的有错误发生了。对 LoadLibrary ，只有返回的 hModule 为 NULL 的时候，GetLastError 才有意义。不检查 hModule 而直接检查 GetLastError 是没有意义的。

cokomowang 2016-02-15

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UE_LOG是一个输出语句。。。。可以忽略

幻夢之葉 2016-02-15

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你两个不同路径的dll版本是否相同？debug就调用debug版本，release就调用release版本，32位64位要区别开来还有该dll依赖的其他dll你是否也放置在\\Plugins\\MyDLL\\ 之下？你测试是不是依赖项的问题，你可以在B工程中把路径修改为你A中的路径尝试下（注意exe跟dll编译版本要一致，调用的dll使用绝对路径以防止测试的时候路径错误）

cokomowang 2016-02-15