我正在尝试使用C++获取PLQ-20 Espon打印机的状态，但没有成功。
我尝试使用带有PASSTHROUGH参数的GDI API和Escape函数，但打印机永远无法理解带有该函数的转义码。
我尝试使用WIN 32 API和此处找到的示例代码。这适用于发送一些转义码，如BEL（使蜂鸣器响起）或FF（Form Feed，从打印机后部弹出纸张），但不适用于ESC O（从打印机前部弹出纸张）、ESC 0 / ESC 1（初始化打印机/重置错误）。
因此，我尝试通过这种方式使用ESC j转义码获取打印机的状态，但没有成功（ReadPrinter函数返回 0）。此外，打印缓冲区似乎不是空的，但我只发送转义命令。
我不知道我是否在发送转义码或尝试读取打印机状态时出错。
如果有人可以发布示例，那么每个人都可以，因为很难在网络上找到它们。
下面是我用来发送命令并读取结果的代码
#include <Windows.h>
#include <StdIO.h>
// **********************************************************************
// PrintError - uses printf() to display error code information
//
// Params:
// dwError - the error code, usually from GetLastError()
// lpString - some caller-defined text to print with the error info
//
// Returns: void
//
void PrintError( DWORD dwError, LPCTSTR lpString )
{
#define MAX_MSG_BUF_SIZE 512
TCHAR *msgBuf;
DWORD cMsgLen;
cMsgLen = FormatMessage( FORMAT_MESSAGE_FROM_SYSTEM |
FORMAT_MESSAGE_ALLOCATE_BUFFER | 40, NULL, dwError,
MAKELANGID(0, SUBLANG_ENGLISH_US), (LPTSTR) &msgBuf,
MAX_MSG_BUF_SIZE, NULL );
printf("%s Error [%d]:: %s\n", lpString, dwError, msgBuf );
LocalFree( msgBuf );
#undef MAX_MSG_BUF_SIZE
}
// end PrintError
// **********************************************************************
// **********************************************************************
// ReadFileWithAlloc - allocates memory for and reads contents of a file
//
// Params:
// szFileName - NULL terminated string specifying file name
// pdwSize - address of variable to receive file bytes size
// ppBytes - address of pointer which will be allocated and contain file bytes
//
// Returns: TRUE for success, FALSE for failure.
//
// Notes: Caller is responsible for freeing the memory using GlobalFree()
//
BOOL ReadFileWithAlloc( LPTSTR szFileName, LPDWORD pdwSize, LPBYTE *ppBytes )
{
HANDLE hFile;
DWORD dwBytes;
BOOL bSuccess = FALSE;
// Validate pointer parameters
if( ( pdwSize == NULL ) || ( ppBytes == NULL ) )
return FALSE;
// Open the file for reading
hFile = CreateFile( szFileName, GENERIC_READ, 0, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL );
if( hFile == INVALID_HANDLE_VALUE )
{
PrintError( GetLastError(), TEXT("CreateFile()") );
return FALSE;
}
// How big is the file?
*pdwSize = GetFileSize( hFile, NULL );
if( *pdwSize == (DWORD)-1 )
PrintError( GetLastError(), TEXT("GetFileSize()") );
else
{
// Allocate the memory
*ppBytes = (LPBYTE)GlobalAlloc( GPTR, *pdwSize );
if( *ppBytes == NULL )
PrintError( GetLastError(), TEXT("Failed to allocate memory\n") );
else
{
// Read the file into the newly allocated memory
bSuccess = ReadFile( hFile, *ppBytes, *pdwSize, &dwBytes, NULL );
if( ! bSuccess )
PrintError( GetLastError(), TEXT("ReadFile()") );
}
}
// Clean up
CloseHandle( hFile );
return bSuccess;
}
// End ReadFileWithAlloc
// **********************************************************************
// **********************************************************************
// RawDataToPrinter - sends binary data directly to a printer
//
// Params:
// szPrinterName - NULL terminated string specifying printer name
// lpData - Pointer to raw data bytes
// dwCount - Length of lpData in bytes
//
// Returns: TRUE for success, FALSE for failure.
//
BOOL RawDataToPrinter( LPTSTR szPrinterName, LPBYTE lpData, DWORD dwCount )
{
HANDLE hPrinter;
DOC_INFO_1 DocInfo;
DWORD dwJob;
DWORD dwBytesWritten;
// Need a handle to the printer.
if( ! OpenPrinter( szPrinterName, &hPrinter, NULL ) )
{
PrintError( GetLastError(), TEXT("OpenPrinter") );
return FALSE;
}
// Fill in the structure with info about this "document."
DocInfo.pDocName = TEXT("My Document");
DocInfo.pOutputFile = NULL;
DocInfo.pDatatype = TEXT("RAW");
// Inform the spooler the document is beginning.
if( (dwJob = StartDocPrinter( hPrinter, 1, (LPBYTE)&DocInfo )) == 0 )
{
PrintError( GetLastError(), TEXT("StartDocPrinter") );
ClosePrinter( hPrinter );
return FALSE;
}
// Start a page.
if( ! StartPagePrinter( hPrinter ) )
{
PrintError( GetLastError(), TEXT("StartPagePrinter") );
EndDocPrinter( hPrinter );
ClosePrinter( hPrinter );
return FALSE;
}
// Send the data to the printer.
if( ! WritePrinter( hPrinter, lpData, dwCount, &dwBytesWritten ) )
{
PrintError( GetLastError(), TEXT("WritePrinter") );
EndPagePrinter( hPrinter );
EndDocPrinter( hPrinter );
ClosePrinter( hPrinter );
return FALSE;
}
/*********************************/
// CODE USED TO READ THE PRINTER
LPBYTE retData = NULL;
LPDWORD bbr = NULL;
if(ReadPrinter(hPrinter, retData, 1, bbr))
{
printf("OUT : %i", retData);
}
else
{
printf("Failed to read printer");
}
/*********************************/
// End the page.
if( ! EndPagePrinter( hPrinter ) )
{
PrintError( GetLastError(), TEXT("EndPagePrinter") );
EndDocPrinter( hPrinter );
ClosePrinter( hPrinter );
return FALSE;
}
// Inform the spooler that the document is ending.
if( ! EndDocPrinter( hPrinter ) )
{
PrintError( GetLastError(), TEXT("EndDocPrinter") );
ClosePrinter( hPrinter );
return FALSE;
}
// Tidy up the printer handle.
ClosePrinter( hPrinter );
// Check to see if correct number of bytes were written.
if( dwBytesWritten != dwCount )
{
//printf( TEXT("Wrote %d bytes instead of requested %d bytes.\n"), dwBytesWritten, dwCount );
return FALSE;
}
return TRUE;
}
// End RawDataToPrinter
// **********************************************************************
int main( int argc, char* argv[] )
{
LPBYTE pBytes = NULL;
int textSize = 2;
DWORD dwSize = textSize;
pBytes = (LPBYTE) malloc (textSize*sizeof(BYTE));
pBytes[0] = 0x1B;
pBytes[1] = 0x6A;
if( ! RawDataToPrinter(L"EPSON PLQ-20 ESC/P2", pBytes, dwSize) )
printf("Failed to send data to printer.\n" );
else
printf("Data sent to printer.\n" );
free(pBytes);
return 0;
}
// end main
// **********************************************************************
谢谢！