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#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <windows.h>
static char buf[256];
static DWORD read_count;
static HANDLE stdin_h;
static OVERLAPPED stdin_o;
static void die(const char* buf) {
fprintf(stderr, "%s\n", buf);
fflush(stderr);
exit(100);
}
static void overlapped_read(void) {
if (ReadFile(stdin_h, buf, sizeof(buf), NULL, &stdin_o)) {
// Since we start the read operation immediately before requesting a write,
// it should never complete synchronously since no data would be available
die("read completed synchronously");
}
if (GetLastError() != ERROR_IO_PENDING) {
die("overlapped read failed");
}
}
static void write(const char* buf, size_t buf_size) {
overlapped_read();
DWORD write_count;
HANDLE stdout_h = GetStdHandle(STD_OUTPUT_HANDLE);
if (!WriteFile(stdout_h, buf, buf_size, &write_count, NULL)) {
die("overlapped write failed");
}
fprintf(stderr, "%ld", write_count);
fflush(stderr);
}
int main(void) {
HANDLE event = CreateEvent(NULL, FALSE, FALSE, NULL);
if (event == NULL) {
die("failed to create event handle");
}
stdin_h = GetStdHandle(STD_INPUT_HANDLE);
stdin_o.hEvent = event;
write("0", 1);
while (1) {
DWORD result = WaitForSingleObject(event, INFINITE);
if (result == WAIT_OBJECT_0) {
if (!GetOverlappedResult(stdin_h, &stdin_o, &read_count, FALSE)) {
die("failed to get overlapped read result");
}
if (strncmp(buf, "exit", read_count) == 0) {
break;
}
write(buf, read_count);
} else {
char emsg[0xfff];
int ecode = GetLastError();
DWORD rv = FormatMessage(
FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS,
NULL,
ecode,
MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
(LPSTR)emsg,
sizeof(emsg),
NULL);
if (rv > 0) {
snprintf(emsg, sizeof(emsg),
"WaitForSingleObject failed. Error %d (%s)", ecode, emsg);
} else {
snprintf(emsg, sizeof(emsg),
"WaitForSingleObject failed. Error %d", ecode);
}
die(emsg);
}
}
return 0;
}
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