Implementation details of alternate screen buffer using virtual codes

[2trvl]

Hi, when I switch to an alternate screen buffer using virtual code ESC[?1049h, STD_OUTPUT_HANDLE remains the same. But the WriteConsole function prints the text to an alternate screen. Do I understand correctly that inside terminal this is not arranged as a series of calls:
CreateConsoleScreenBuffer
SetConsoleScreenBufferSize
SetConsoleActiveScreenBuffer
SetStdHandle

And the alternate screen is software-based that isn't handled by underlaying API's. At the same time, the buffer created in Windows API is successfully closes using the ANSI ESC code ESC[?1049l.

If it's not, how would I be able to detect from Windows Console API that the screen is switched.

[j4james]

I don't think you can detect the alternate buffer status with a Console API call, and if you could, it's probably not something you should rely on. However, you can query that state with a standard DECRQM escape sequence. If you output \x1b[?1049$p, you should get back one of two responses:

• \x1b[?1049;1$y if you're in the alternate buffer
• \x1b[?1049;2$y if you're in the main buffer

That said, you should be aware that not all terminals will respond to DECRQM, and it has only been supported in Windows Terminal since version 1.17.