From 672802955590cf03b623dad2a82de2a210d4e08e Mon Sep 17 00:00:00 2001
From: aleks <aleks@local>
Date: Thu, 16 Jul 2026 14:10:27 +0300
Subject: [PATCH] fix: set stdout to O_BINARY on Windows to prevent READY
 sentinel corruption
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Both sentinels in c/coli (READY and END) end with \n. Under CRT text
mode on Windows, printf() translates \n to \r\n, so the engine emits
\x01\x01READY\x01\x01\r\n. The Python coli wrapper checks
endswith(SENTINEL) which expects bare \n — the match never fires and
chat hangs forever.

_setmode(fileno(stdout), O_BINARY) at engine startup switches stdout
to binary mode so \n passes through unchanged. This matches the
belt-and-braces reasoning already in compat.h:88 (O_BINARY for file
I/O). The fix is defense-in-depth: on the documented w64devkit/MinGW
build path, CRT text mode may or may not apply depending on how the
terminal is attached, so this ensures correctness regardless.

Note: I was unable to compile-test this on the full codebase because
glm.c uses POSIX-only symbols (mmap, madvise, select, fd_set, struct
stat/fstat) that are unavailable on Windows without platform guards.
The codebase compiles on Linux (Ubuntu 24.04, GCC 13) and macOS
(Apple clang). Windows compilation requires wrapping those POSIX calls
in #if defined(__APPLE__) || defined(__linux__) || defined(__FreeBSD__)
guards — I opened this as a separate concern for the maintainer.
---
 c/glm.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/c/glm.c b/c/glm.c
index 00c7076..bf270b9 100644
--- a/c/glm.c
+++ b/c/glm.c
@@ -5749,6 +5749,9 @@ int main(int argc, char **argv){
         perror("[OMP] execv self-reexec failed, running untuned");
 #endif
     }
+#ifdef _WIN32
+    _setmode(fileno(stdout), O_BINARY);
+#endif
 #if defined(__AVX512F__) && defined(__AVX512BW__)
     if(getenv("I4_ACC512")) g_i4_acc512=atoi(getenv("I4_ACC512"))!=0;
     if(getenv("I4_ACC512_TEST")){