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FB使用入口点函数例子

news 来源：原创 2024/5/20 23:08:16

一、DLL的入口点

1.1 VFB的自带DLL模式入口

FB是把代码转成C（GCC编译）或者汇编（GAS编译）后编译的，本身就有一个main函数，所以在程序里其实不需要入口点，直接写就可以顺序执行，而有的小伙伴编译DLL时，想使用DLL入口点函数的参数。而VFB只提供了DLL加载和DLL卸载两种（使用的是Constructor和Destructor来实现加载和卸载功能的），其实现方式如下（可以直接使用VFB的DLL模式，IDE已经实现，不需要写代码）：

'===================================================================================================================
'该方法没有线程启动和终止的参数
'使用Constructor和Destructor来判断加载和卸载调用，以此设置fdwReason参数,具体如下：
'获取当前模块句柄
Function GetCurrentModuleHandle() As HMODULE
    dim info As MEMORY_BASIC_INFORMATION
    VirtualQuery(cast(LPCVOID,@GetCurrModuleHandle),@info,SizeOf(info))
    Return cast(HMODULE,info.AllocationBase)
End Function
 
'DLL入口函数 
Function DllMain(ByVal hModule As HANDLE, ByVal fdwReason As Dword, ByVal lpReserved As LPVOID) As BOOL Export 
    Select Case fdwReason
    	Case DLL_PROCESS_ATTACH  'DLL被加载
            MessageBox(0,"DLL_PROCESS_ATTACH","hModule=" & Hex(hModule),0)
    	Case DLL_PROCESS_DETACH  'DLL被卸载
            MessageBox(0,"DLL_PROCESS_DETACH","hModule=" & Hex(hModule),0)
    End Select  
    Function = TRUE
End Function

'DLL启动时调用
Sub LoadDllMain() Constructor
	DllMain(GetCurrentModuleHandle(),DLL_PROCESS_ATTACH,NULL)
End Sub

'DLL卸载时调用
Sub UnloadDllMain() Destructor
	DllMain(GetCurrentModuleHandle(),DLL_PROCESS_DETACH,NULL)
End Sub

1.2 Windows的标准入口

如果有需要线程启动和终止消息的，则需要使用这种模式的入口，需要自己复制代码实现，主要原理是通过参数命令-Wl -e增加一个入口点函数_DLLENTRY （在VFB附加编译选项中输入命令：-Wl -e_DLLENTRY，如果使用1.09.0的编译器，也可以使用 #cmdline来设置编译参数）。这里需要注意，32位和64位编译产生的函数名有区别（64位前面有下划线，而32位没有），代码如下：

'===================================================================================================================
'线程测试
Dim Shared pThread As HANDLE

Function TestThread(ByVal dat As Any Ptr) As DWORD       
    Print "hModule=";*Cast(HANDLE Ptr,dat)
	Print "in thread"
    Return 0                                                         
End Function   
'线程测试
'===================================================================================================================

'===================================================================================================================
'该方法使用-Wl编译命令来设置入口点
'编译命令如下：fbc -s gui -dll -export -Wl -e_DLLENTRY 
#cmdline "-Wl -e_DLLENTRY"   '添加入口命令（fbc编译器支持的情况下）
#Ifdef __FB_64BIT__
Function DllMain Alias "_DLLENTRY" (ByVal hModule As HANDLE, ByVal fdwReason As DWORD, ByVal lpReserved As LPVOID) As BOOL Export 
#Else
Function DllMain Alias "DLLENTRY" (ByVal hModule As HANDLE, ByVal fdwReason As DWORD, ByVal lpReserved As LPVOID) As BOOL Export 
#EndIf 
    Select Case fdwReason
    	Case DLL_PROCESS_ATTACH  'DLL被加载
            MessageBox(0,"DLL被加载","hModule=" & Hex(hModule),0)
'===================================================================================================================
'线程测试
            Dim dwID As DWORD 
            pThread = CreateThread(NULL,0,Cast(LPTHREAD_START_ROUTINE,@TestThread),@hModule,0,@dwID) '开启线程
'线程测试
'===================================================================================================================
    	Case DLL_PROCESS_DETACH  'DLL被卸载
            MessageBox(0,"DLL被卸载","hModule=" & Hex(hModule),0)
'===================================================================================================================
'线程测试
            CloseHandle(pThread) '关闭线程
            pThread = NULL 
'线程测试
'===================================================================================================================
    	Case DLL_THREAD_ATTACH   '单个线程启动
            MessageBox(0,"单个线程启动","hModule=" & Hex(hModule),0)
    	Case DLL_THREAD_DETACH   '单个线程终止
    		MessageBox(0,"单个线程终止","hModule=" & Hex(hModule),0)
    	Case Else
    End Select  
    Function = TRUE
End Function

FBEdit测试工程如下：https://github.com/rainheart311/FBEdit-FullProject/tree/main/Enter%20Point%20%20FreeBASIC/DllMain

二、WinMain入口点

Function WinMain(ByVal hInst As HINSTANCE,ByVal hPrevInst As HINSTANCE,ByVal CmdLine As LPCTSTR,ByVal CmdShow As Integer) As LRESULT
    '这里创建窗体
End Function

'{ Program start
    WinMain(GetModuleHandle(NULL),NULL,GetCommandLine,SW_SHOWDEFAULT) '这里调用入口点函数
    End
'}
'Program End

FBEdit测试工程如下：

https://github.com/rainheart311/FBEdit-FullProject/tree/main/Enter%20Point%20%20FreeBASIC/WinMain

三、Main入口点

Function Main(ByVal argc As Integer,ByVal argv As ZString Ptr Ptr ) As Integer      
    print "param";argc,**argv  '显示参数值
    print "end"   
    Sleep     
	Return True    
End Function


End Main(__FB_ARGC__,__FB_ARGV__)   '调用入口函数，__FB_ARGC__,__FB_ARGV__是控制台传入的参数

FBEdit测试工程如下：

FBEdit-FullProject/Enter Point FreeBASIC/Main at main · rainheart311/FBEdit-FullProject · GitHub