Source code of Windows XP (NT5)
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346 lines
7.5 KiB

#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include "windows.h"
unsigned char writebuff[10][10000];
OVERLAPPED WriteOl[10];
HANDLE hFile;
HANDLE StartTrailingWriteEvent;
HANDLE EndedTrailingWrites;
DWORD
QueueOtherWrites(
LPVOID Trash
)
{
DWORD k;
UNREFERENCED_PARAMETER(Trash);
WaitForSingleObject(StartTrailingWriteEvent,-1);
printf("Wait Satisfied Sleeping for 3 seconds\n");
Sleep(3000);
for (
k = 5;
k <= 9;
k++
) {
DWORD NumberWritten;
BOOL WriteDone;
WriteDone = WriteFile(
hFile,
writebuff[k],
10000,
&NumberWritten,
&WriteOl[k]
);
if (!WriteDone) {
DWORD LastError;
LastError = GetLastError();
if (LastError != ERROR_IO_PENDING) {
printf("Status of failed write %d is: %d\n",k,LastError);
}
}
}
printf("Trailing Writes are all queued thread waits until all are done\n");
WaitForSingleObject(EndedTrailingWrites,-1);
return 1;
}
void main(int argc,char *argv[]) {
DCB MyDcb;
char *MyPort = "COM1";
DWORD j;
DWORD ThreadId;
DWORD Errors;
COMSTAT LocalStat;
if (argc > 1) {
MyPort = argv[1];
}
for (
j = 0;
j <= 9;
j++
) {
if (!(WriteOl[j].hEvent = CreateEvent(
NULL,
FALSE,
FALSE,
NULL
))) {
printf("Could not create the write event %d.\n",j);
} else {
WriteOl[j].Internal = 0;
WriteOl[j].InternalHigh = 0;
WriteOl[j].Offset = 0;
WriteOl[j].OffsetHigh = 0;
}
}
if (!(StartTrailingWriteEvent = CreateEvent(
NULL,
TRUE,
FALSE,
NULL
))) {
printf("Could not create trailing write event\n");
goto cleanup;
}
if (!(EndedTrailingWrites = CreateEvent(
NULL,
TRUE,
FALSE,
NULL
))) {
printf("Could not create ending trailing write event\n");
goto cleanup;
}
if ((hFile = CreateFile(
MyPort,
GENERIC_READ | GENERIC_WRITE,
0,
NULL,
CREATE_ALWAYS,
FILE_ATTRIBUTE_NORMAL | FILE_FLAG_OVERLAPPED,
NULL
)) != ((HANDLE)-1)) {
printf("We successfully opened the %s port.\n",MyPort);
//
// Create the thread that will wait for the
// trailing write event before it queues its reads.
//
if (!CreateThread(
NULL,
0,
QueueOtherWrites,
NULL,
0,
&ThreadId
)) {
printf("Could not create the second thread.\n");
goto cleanup;
}
//
// We've successfully opened the file. Set the state of
// the comm device. First we get the old values and
// adjust to our own.
//
if (!GetCommState(
hFile,
&MyDcb
)) {
printf("Couldn't get the comm state: %d\n",GetLastError());
exit(1);
}
MyDcb.BaudRate = 19200;
MyDcb.ByteSize = 8;
MyDcb.Parity = NOPARITY;
MyDcb.StopBits = ONESTOPBIT;
if (SetCommState(
hFile,
&MyDcb
)) {
DWORD k;
for (
k = 0;
k <= 4;
k++
) {
DWORD NumberWritten;
BOOL WriteDone;
WriteDone = WriteFile(
hFile,
writebuff[k],
10000,
&NumberWritten,
&WriteOl[k]
);
if (!WriteDone) {
DWORD LastError;
LastError = GetLastError();
if (LastError != ERROR_IO_PENDING) {
printf("Status of failed write %d is: %d\n",k,LastError);
goto cleanup;
}
}
}
SetEvent(StartTrailingWriteEvent);
if (!FlushFileBuffers(hFile)) {
printf("Couldn't flush %d\n",GetLastError());
} else {
printf("Flushed\n");
}
//
// Insure that the first five writes are done.
//
for (
k = 0;
k <= 4;
k++
) {
DWORD NumberTransferred;
if (!GetOverlappedResult(
hFile,
&WriteOl[k],
&NumberTransferred,
FALSE
)) {
printf("Write %d was not complete!!\n",k);
} else {
if (NumberTransferred != 10000) {
printf("Write %d transferred only %d bytes\n",k,NumberTransferred);
}
}
}
//
// Wrap around until the count is zero.
//
LocalStat.cbOutQue = 1;
while (LocalStat.cbOutQue) {
if (!ClearCommError(
hFile,
&Errors,
&LocalStat
)) {
printf("Couldn't call ClearCommError: %d\n",GetLastError());
exit(1);
}
if (Errors) {
printf("For some odd reason we had errors: %x\n",Errors);
}
printf("Currently in output queue: %d\n",LocalStat.cbOutQue);
Sleep(2000);
}
//
// Wait for the last writes to complete.
//
for (
k = 9;
k >= 5;
k--
) {
DWORD NumberTransferred;
if (!GetOverlappedResult(
hFile,
&WriteOl[k],
&NumberTransferred,
TRUE
)) {
printf("Bad status from write %d status is %d\n",k,GetLastError());
} else {
if (NumberTransferred != 10000) {
printf("Write %d transferred only %d bytes\n",k,NumberTransferred);
}
}
}
SetEvent(EndedTrailingWrites);
} else {
printf("Couldn't set the comm state\n");
}
} else {
printf("Couldn't open the comm port\n");
}
cleanup:;
}