How to send data to a POS Printer via USB

[Yany]

I need to send a string or char to a "POS Receipt Printer" via USB.

My problem is how to establish a communication with the printer by USB port in C++ (I'm using MFC)

I tried this:

HANDLE dev = CreateFile(
"\\\\.\\USB001",
GENERIC_READ | GENERIC_WRITE,
FILE_SHARE_READ | FILE_SHARE_WRITE,
NULL,
OPEN_EXISTING,
FILE_ATTRIBUTE_NORMAL,
NULL);

if(dev!=INVALID_HANDLE_VALUE)
{
DWORD dwWritten = 0;
LPCSTR lpszTest = "Hello world!";
::WriteFile(dev, lpszTest, strlen(lpszTest), &dwWritten, NULL);
::CloseHandle(dev);
}

but, it returns by GetLastError() the value = 2 (Can not find the specified file)


Also, I tried this:

HANDLE dev;

CString s("\\\\.\\USB001");
LPWSTR p=(LPWSTR)(LPCTSTR)s;
if(OpenPort(p,(PHANDLE)&dev))
{
CString str = "Hello world!";
LPBYTE pByte = new BYTE[str.GetLength()+1];
memcpy(pByte,(VOID*)LPCTSTR(str),str.GetLength());
LPDWORD r;
r=0;

WritePort(dev,pByte,6,r);

delete [] pByte;
}

But I got frustrated,
due that OpenPort and WritePort belongs to #include <winsplp.h> and <winspool.h> , so it generates a lot of dependencies(Libs,dlls) that escapes my knowledge.


If anyone can help me, I'll really appreciate it.

[Thomas1965]

Try this example:
https://support.microsoft.com/en-us/help/138594/howto-send-raw-data-to-a-printer-by-using-the-win32-api

[Yany]

Thank you Thomas. It worked!
This link was the key!
The whole day prowling, analyzing this example code, finally I got the solution.
Very thankful.