www.pudn.com > 2004-01-16_SimSerial.rar > main.c

#include "windows.h" 
#include "stdio.h" 
#include "main.h" 
 
#define READ_BUF_SIZE 256 
#define READ_TIMEOUT      5000      // milliseconds 
#define EVENTFLAG_DEFAULT	EV_BREAK | EV_CTS | EV_DSR | EV_ERR | EV_RING | EV_RLSD 
 
void main(int argc, char *argv[] ) 
{ 
	HANDLE	hComm; 
	DWORD	dwRead; 
	BOOL	fWaitingOnRead = FALSE; 
	OVERLAPPED osReader = {0}; 
	BYTE	lpBuf[ READ_BUF_SIZE ]; 
	DWORD dwRes; 
	COMMTIMEOUTS CommTimeouts = { 0 }; 
	DCB   dcb = { 0 }; 
	OVERLAPPED osStatus = { 0 }; 
	DWORD dwCommEvent; 
	 
	hComm = CreateFile( "COM5", 
		GENERIC_READ | GENERIC_WRITE,  
		0,  
		0,  
		OPEN_EXISTING, 
		FILE_ATTRIBUTE_NORMAL | FILE_FLAG_OVERLAPPED, 
		0); 
	if( hComm == INVALID_HANDLE_VALUE ){ 
		printf("CreateFile failed with code 0x%x\n", GetLastError() ); 
		goto FAILED; 
	} 
	if( !GetCommTimeouts( hComm, &CommTimeouts ) ){ 
		printf("GetCommTimeouts failed with code 0x%x\n", GetLastError() ); 
		goto FAILED; 
	} 
	dcb.DCBlength = sizeof( DCB ); 
	if( !GetCommState( hComm, &dcb ) ){ 
		printf("GetCommState failed with code 0x%x\n", GetLastError() ); 
		goto FAILED; 
	} 
	osStatus.hEvent = CreateEvent(NULL, TRUE, FALSE, NULL); 
	if( osStatus.hEvent == NULL ){ 
		printf("CreateEvent(Status Event) failed\n"); 
		goto FAILED; 
	} 
	dwRes = SetCommMask( hComm, EVENTFLAG_DEFAULT ); 
	dwRes = 0; 
	dwRes = WaitCommEvent( hComm, &dwCommEvent, &osStatus ); 
	if( dwRes ){ 
		printf("WaitCommEvent OK\n"); 
	}else{ 
		dwRes = WaitForSingleObject( osStatus.hEvent, 3000 ); 
		switch( dwRes ){ 
		case WAIT_OBJECT_0: 
			printf("Event is set\n"); 
			break; 
		case WAIT_TIMEOUT: 
			printf("Timeout\n"); 
			break; 
		} 
	} 
 
	CloseHandle( osStatus.hEvent ); 
FAILED: 
	CloseHandle( hComm ); 
} 
void HandleASuccessfulRead( LPBYTE lpBuf, int dwRead ) 
{ 
	printf("In HandleASuccessfulRead routine\n"); 
} 
 
#if 0 
	// Create the overlapped event. Must be closed before exiting 
	// to avoid a handle leak. 
	osReader.hEvent = CreateEvent(NULL, TRUE, FALSE, NULL); 
	 
	if (osReader.hEvent == NULL){ 
		printf("osReader.hEvent failed\n"); 
		goto FAILED; 
	} 
	if (!fWaitingOnRead) { 
		// Issue read operation. 
		if (!ReadFile(hComm, lpBuf, READ_BUF_SIZE, &dwRead, &osReader)) { 
			if (GetLastError() != ERROR_IO_PENDING)     // read not delayed? 
				printf("ReaderFile return immediately\n"); 
			// Error in communications; report it. 
			else 
				fWaitingOnRead = TRUE; 
		} 
		else {     
			// read completed immediately 
			HandleASuccessfulRead(lpBuf, dwRead); 
		} 
	} 
	if (fWaitingOnRead) { 
		dwRes = WaitForSingleObject(osReader.hEvent, READ_TIMEOUT); 
		switch(dwRes) 
		{ 
			// Read completed. 
		case WAIT_OBJECT_0: 
			if (!GetOverlappedResult(hComm, &osReader, &dwRead, FALSE)){ 
				// Error in communications; report it. 
				printf("Read completed but no data\n"); 
			} 
			else{ 
				// Read completed successfully. 
				HandleASuccessfulRead(lpBuf, dwRead); 
			} 
			//  Reset flag so that another opertion can be issued. 
			fWaitingOnRead = FALSE; 
			break; 
			 
		case WAIT_TIMEOUT: 
			// Operation isn't complete yet. fWaitingOnRead flag isn't 
			// changed since I'll loop back around, and I don't want 
			// to issue another read until the first one finishes. 
			// 
			// This is a good time to do some background work. 
			printf("Time out\n"); 
			break;                        
			 
		default: 
			// Error in the WaitForSingleObject; abort. 
			// This indicates a problem with the OVERLAPPED structure's 
			// event handle. 
			break; 
		} 
	} 
	CloseHandle( osReader.hEvent ); 
#endif