5.2使用select,poll

时间:2023-03-09 06:03:56
5.2使用select,poll

5.2 使用select,poll   // CPU占用率低,适用于很多简单场合

参考:UNIX环境高级编程 I/O多路转接

监测多个文件,只要有某一个文件可读/可写/异常或超时,即返回
int select(int nfds,    fd_set *readfds, fd_set *writefds,fd_set *exceptfds, struct timeval *timeout);
                最大文件句柄+1   被监测是否可读的文件                                         超时时间
                                               被监测是否可写的文件
                                                                被监测是否有异常的文件

修改

int AllInputDevicesInit(void)
{
PT_InputOpr ptTmp = g_ptInputOprHead;
int iError = -1; FD_ZERO(&g_tRFds); while (ptTmp)
{
if (0 == ptTmp->DeviceInit())
{
FD_SET(ptTmp->iFd, &g_tRFds);
if (g_iMaxFd < ptTmp->iFd)
g_iMaxFd = ptTmp->iFd;
iError = 0;
}
ptTmp = ptTmp->ptNext;
} g_iMaxFd++;
return iError;
} int GetInputEvent(PT_InputEvent ptInputEvent)
{
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*/
PT_InputOpr ptTmp = g_ptInputOprHead;
fd_set tRFds;
int iRet; tRFds = g_tRFds; iRet = select(g_iMaxFd, &tRFds, NULL, NULL, NULL);
if (iRet > 0)
{
while (ptTmp)
{
if (FD_ISSET(ptTmp->iFd, &tRFds))
{
if(0 == ptTmp->GetInputEvent(ptInputEvent))
{
return 0;
}
}
ptTmp = ptTmp->ptNext;
}
}
return -1;
}