調用外部程式

今天在工作中，需要在C++程式中調用其它的可執行程式，在網上搜羅了一些，感覺很零碎，現整理如下，希望能對一些人有所幫助：

C語言：

1._execl函數家庭。

Each function in this family loads and executes a new process:

_execl, _wexecl	_execv, _wexecv
_execle, _wexecle	_execve, _wexecve
_execlp, _wexeclp	_execvp, _wexecvp
_execlpe, _wexeclpe	_execvpe, _wexecvpe

The letter at the end of the function name determines the variation.

Each function in this family loads and executes a new process:

_execl, _wexecl	_execv, _wexecv
_execle, _wexecle	_execve, _wexecve
_execlp, _wexeclp	_execvp, _wexecvp
_execlpe, _wexeclpe	_execvpe, _wexecvpe

The letter at the end of the function name determines the variation.

_exec function suffix	Description
e	envp, array of pointers to environment settings, is passed to the new process.
l	Command-line arguments are passed individually to _exec function. Typically used when the number of parameters to the new process is known in advance.
p	PATH environment variable is used to find the file to execute.
v	argv, array of pointers to command-line arguments, is passed to _exec. Typically used when the number of parameters to the new process is variable.

2._spawnl函數家庭

Each of the _spawn functions creates and executes a new process:

_spawnl, _wspawnl	_spawnv, _wspawnv
_spawnle, _wspawnle	_spawnve, _wspawnve
_spawnlp, _wspawnlp	_spawnvp, _wspawnvp
_spawnlpe, _wspawnlpe	_spawnvpe, _wspawnvpe

e、l、p、v 的含義同1.

3.system

用法：system函數是執行shell指令，在windows下就是将指令交給DOS或cmd.exe去執行。如果要改變c:/windows/下檔案名為myfile.txt檔案為隻讀屬性，可以執行： 

system("attrib +r c:/windows/myfile.txt"); 

注：用VC++編寫源程式時，system應該寫為System

總結：

相同點：三者都可以建立一個新程序；

不同點：_execl與system建立一個新程序後不傳回，相當于建立的新程序替換了原來的調用程序；而_spawnl建立一個新程序後，原來的調用程序依然存在，并繼續執行。

注意：system在windows和linux中都可以使用，但由于windows和linux下的指令不同，它能調用的指令也不同。如linux下能調用system("ls")，但由于windows下沒有ls指令，是以不能調用。

VC++：

1 WinExec

原型:

UINT WinExec(

LPCSTR lpCmdLine, // address of command line

UINT uCmdShow      // window style for new application

);

用于十六位作業系統及相容系統.

例如:

WinExec("notepad.exe f://調用程式.txt",SW_SHOW);

WinExec("notepad.exe ",SW_SHOW);

不同的參數用空格分開,故路徑中不能有空格,而大部分程式預設是安裝在".../Program Files/...",如word,這極大的限制了WinExec的應用範圍.

以上可不帶路徑:

1,程式所在目錄.

2,目前路徑.

3,系統目錄,可以用GetSystemDirectory得到.

4,Windows 目錄. 可以用TheGetWindowsDirectory得到. 

5,在環境變量中設定的目錄.

2 ShellExecute

原型:

HINSTANCE ShellExecute(

    HWND hwnd,                   //父視窗句柄

    LPCTSTR lpOperation,         //操作,"open","print","explore"

    LPCTSTR lpFile,              //檔案名,前面可加路徑

    LPCTSTR lpParameters,        //參數

    LPCTSTR lpDirectory,         //預設檔案夾

    INT nShowCmd                 //顯示方式

);

打開一個應用程式

ShellExecute(this->m_hWnd,"open","calc.exe","","", SW_SHOW );

或

ShellExecute(this->m_hWnd,"open","notepad.exe","c:/MyLog.log","",SW_SHOW );

打開一個同系統程式相關連的文檔

ShellExecute(this->m_hWnd,"open","c:/abc.txt","","",SW_SHOW );

激活相關程式，發送EMAIL

ShellExecute(this->m_hWnd,"open","mailto:[email protected]","","", SW_SHOW );

用系統列印機列印文檔

ShellExecute(this->m_hWnd,"print","c:/abc.txt","","", SW_HIDE);

lpParameters的用法示例:

一,建立一個可以接受參數的程式call.exe,添加如下代碼:

BOOL CCallApp::InitInstance()

{

int n = __argc;

for(int i = 1 ; i < n ; i++)

AfxMessageBox(__targv[i]);

       //__targv[0]存儲的是程式的檔案名

...

}

二,Alt + F7的進行Project setting, Debug -> program argurments ->"1 2 3 4 5".

如果有多個參數,用空格分開.

三,運作.

四,執行ShellExecute(NULL,NULL,"f://call.exe","1 2 3 4 5",NULL,SW_SHOW);

3 CreateProcess

BOOL CreateProcess(

LPCTSTR lpApplicationName,

LPTSTR lpCommandLine, 

LPSECURITY_ATTRIBUTES lpProcessAttributes, 

LPSECURITY_ATTRIBUTES lpThreadAttributes, 

BOOL bInheritHandles, 

DWORD dwCreationFlags,

LPVOID lpEnvironment, 

LPCTSTR lpCurrentDirectory, 

LPSTARTUPINFO lpStartupInfo, 

LPPROCESS_INFORMATION lpProcessInformation 

);

STARTUPINFO   startupInfo;

memset(&startupInfo,0,sizeof(STARTUPINFO));

startupInfo.cb = sizeof(STARTUPINFO);

示例:

//程式最啟動時最大化 

startupInfo.dwFlags |= STARTF_USESHOWWINDOW;

startupInfo.wShowWindow = SW_SHOWMAXIMIZED;

//運作....exe

PROCESS_INFORMATION ProcessInfo;

BOOL bCreate = ::CreateProcess

        (

        "f://call.exe",// 1 2 3 4",

NULL,

NULL,

        NULL,

        FALSE,

        0,

        NULL,

        NULL,

        &startupInfo,

        &ProcessInfo);

//等到call.exe執行完畢

WaitForSingleObject(ProcessInfo.hProcess,1000000);

MessageBox("調用程式結束!");

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