CopyConsoleScreen.c

#include <stdio.h>
#include <stdlib.h>
#include <Windows.h>

int
main(int argc, char *argv[]) {
  char* buffer;
  BOOL bStatus;
  COORD coords;
  HANDLE hConsole;
  DWORD dwRead, dwLength;
  DWORD dwCursorOffset, dwStartOffset;
  CONSOLE_SCREEN_BUFFER_INFOEX info;
  FILE* outputFile;

  if (argc == 1 || argc > 2) {
    fprintf(stderr, "Usage: %s /path/to/file\n", argv[0]);
    exit(0);
  }
  
  hConsole = GetStdHandle(STD_OUTPUT_HANDLE);

  if (!hConsole || hConsole == INVALID_HANDLE_VALUE) {
    fprintf(stderr, "ERORR: failed to obtain standard handle\n");
  }

  info.cbSize = sizeof(CONSOLE_SCREEN_BUFFER_INFOEX);
  bStatus = GetConsoleScreenBufferInfoEx(hConsole, &info);

  if (bStatus) {
  }

  dwCursorOffset = info.dwMaximumWindowSize.X
    * info.dwCursorPosition.Y + info.dwCursorPosition.X;

  dwStartOffset = max(0,
    dwCursorOffset - min(dwCursorOffset, 65535));

  dwLength = dwCursorOffset - dwStartOffset;

  // TODO: overflow? align to start of line?
  coords.X = (dwStartOffset % info.dwMaximumWindowSize.X);
  coords.Y = (dwStartOffset / info.dwMaximumWindowSize.X);

  buffer = (char*)malloc(dwLength);

  if (!buffer) {
  }

  bStatus = ReadConsoleOutputCharacterA(hConsole, (LPSTR)buffer,
    dwLength, coords, &dwRead);

  if (bStatus) {
  }

  outputFile = fopen(argv[1], "wb");

  if (outputFile) {
    size_t written = fwrite(buffer, sizeof(*buffer), dwLength, outputFile);
    if (written != dwLength) {
    }
    fclose(outputFile);
  } else {
    fprintf(stderr, "ERROR: failed to open output file\n");
  }

  return EXIT_SUCCESS;
}