Hello,

I am using two maxsteram XTEND modems. i am havnig some trouble doing some simple io.

i send a string "hello" from one to the other in a loop. if i send less than 500 tiems, it works. .. if i try to send more than 500 times, the receving end receives the string as "eohell".. i am using non overlapped io.

sending code (this works since we have "while (i<500)".. if i make it "while (true)" or "while (i<600)" it does not work)... i have marked the line with "//HERE********************" in the code.. i have also marked two other lines that i would like you to see (with waitcommevent).

Code:
int main(){

	HANDLE hport;
	hport=CreateFile("COM1:", GENERIC_READ | GENERIC_WRITE, 0, NULL, OPEN_EXISTING,0,NULL);
	DWORD dwCommEvent;
	if (hport==INVALID_HANDLE_VALUE ){
		std::cout<<"PORT UNAVAILABLE"<<std::endl;
	}
	else{
		initcomport(hport);
		SetCommMask(hport, EV_CTS|EV_DSR);
		char * test="hello";
		int i=0;
		while (i<500){ //HERE********************
			DWORD dwNumBytesWritten;
			int bsent=0;
			while (bsent<buffersize){
				WriteFile(hport, test+bsent, buffersize-bsent, &dwNumBytesWritten, NULL);
								bsent=bsent+dwNumBytesWritten;
			}
			
				//WaitCommEvent(hport, &dwCommEvent, NULL);//HERE********************
			
			//dwCommEvent=0;//HERE********************
			i++;
		}
	}//close else

	return 0;
}
receiving code:
Code:
int main(){

	HANDLE hport;
	hport=CreateFile("COM1:", GENERIC_READ | GENERIC_WRITE, 0, NULL, OPEN_EXISTING,0,NULL);
		if (hport==INVALID_HANDLE_VALUE ){
		std::cout<<"PORT UNAVAILABLE"<<std::endl;
	}

	initcomport(hport); //function to initialize the port.


	
	char * test=new char [buffersize+1];

	while (true){
		DWORD dwBytesTransferred=0;
		int brec=0;
		while (brec<buffersize){
			ReadFile(hport,test+brec,buffersize-brec,&dwBytesTransferred,NULL);
			brec=brec+dwBytesTransferred;
			//test[dwBytesTransferred]='\0';
		}
				test[buffersize]='\0';
				std::cout<<"Buffer is: "<<test<<std::endl;
							
		}




	return 0;
}
It seems that i have some sort of synchrozniation issue here... i tried using "WaitCommEvent()".. but it waits indefinitely when i use that... (this can be seen in the commented liens in the sending part)..

what i'm really looking for is to know when the modem is ready to send out more data and when the modem is ready to receive. i hope someone can h elp me out!

thanks a lot!
drew.