c++调用子进程捕获输出(windows,linux)

Posted 2021-08-30 qianbo_insist

1、windows

在windows上使用API函数CreateProcessW函数或者winexe 来启动新的进程，执行cmd命令：

int execute(const TCHAR *childexe)   
{   

    SECURITY_ATTRIBUTES sa = {0};                                              
    HANDLE hRead = NULL, hWrite = NULL;                                                
    sa.nLength = sizeof(SECURITY_ATTRIBUTES);    
    sa.lpSecurityDescriptor = NULL;    
    sa.bInheritHandle = TRUE;    
    if (!CreatePipe(&hRead, &hWrite, &sa,0))                             
    {    
        return false;    
    }    
    HANDLE hTemp = GetStdHandle(STD_OUTPUT_HANDLE);
	SetStdHandle(STD_OUTPUT_HANDLE,hTemp);
	
    STARTUPINFO si = {0};    
    PROCESS_INFORMATION pi = {0};    
    si.cb = sizeof(STARTUPINFO);    
    GetStartupInfo(&si);   
    si.hStdError = hWrite;                                              
    si.hStdOutput = hWrite;                                                       si.wShowWindow = SW_HIDE;    
    si.dwFlags = STARTF_USESHOWWINDOW | STARTF_USESTDHANDLES;    
    bRet = CreateProcess(NULL,childexe,NULL,NULL,TRUE,NULL,NULL,NULL,&si,&pi);
    if (!bRet))             
    {    
        CloseHandle(hWrite);   
        CloseHandle(hRead);   
        return false;   
    }    
    
	
	CloseHandle(hWrite);
	char ReadBuff[256] = {0};
	while(ReadFile(hRead,ReadBuff,256,&ReadNum,NULL))
	{
		ReadBuff[ReadNum] = '\\0';
		cout << ReadBuff << "--" << ReadNum << endl;
	}
	cin.get();
	return 0;

    //WaitForSingleObject(pi.hProcess,INFINITE);                            
    //CloseHandle(pi.hProcess);                                             
    //CloseHandle(pi.hThread);                                           
    //CloseHandle(hWrite);                                                  
    //ReadFile(hRead, buffer, MAX_PATH_LENGTH, &bytesRead, NULL);           
    //CloseHandle(hRead);                                                   
  
}  

2、linux

1 system函数可以运行命令行
2 popen打开一个命令行的管道
3 通过fgets获得该管道传输内容

在linux上运行的例子如下：

int g_stop = 0;
void execute(const char *cmd)   
{   
    char buf_ps[1024];   
    char ps[1024]={0};   
    FILE *ptr;   
    strcpy(ps, cmd);   
    if((ptr=popen(ps, "r"))!=NULL)   
    {   
        while(fgets(buf_ps, 1024, ptr)!=NULL)   
        {   
           printf("%s\\n",buf_ps);
           if(g_stop == 1)
              break;
        }   
        pclose(ptr);   
        ptr = NULL;   
    }   
    else  
    {   
        printf("popen %s error\\n", ps);   
    }   
}  

说明：
1、参数cmd为要执行的命令行，result为命令行运行结果。
2 、输入的cmd命令用… 2>&1 的形式，可以将标准错误读进来