How to send data to a POS Printer via USB

Yany (20)

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.
Yany (20)
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.
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