From 93834dbbf88ad82c93ae43e3c40dd9944670112d Mon Sep 17 00:00:00 2001
From: "Juergen E. Fischer" <jef@norbit.de>
Date: Sun, 4 Jan 2026 16:42:29 +0100
Subject: [PATCH] disable unity build for server on msvc

---
 src/server/CMakeLists.txt | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/src/server/CMakeLists.txt b/src/server/CMakeLists.txt
index be80477d1f0a..b54676b626e6 100644
--- a/src/server/CMakeLists.txt
+++ b/src/server/CMakeLists.txt
@@ -100,7 +100,12 @@ if (USE_PRECOMPILED_HEADERS)
   target_precompile_headers(qgis_server PRIVATE $<$<COMPILE_LANGUAGE:CXX>:${CMAKE_SOURCE_DIR}/src/core/qgis.h>)
 endif()
 
-set_target_properties(qgis_server PROPERTIES UNITY_BUILD ${ENABLE_UNITY_BUILDS})
+# fcgi's stdio hacks fail in unity builds on msvc (see https://cdash.orfeo-toolbox.org/viewBuildError.php?buildid=37453)
+# Example:
+# …\include\__msvc_filebuf.hpp(86): error C2664: 'wint_t fgetwc(FILE *)': cannot convert argument 1 from 'FCGI_FILE *' to 'FILE *'
+if(NOT MSVC)
+  set_target_properties(qgis_server PROPERTIES UNITY_BUILD ${ENABLE_UNITY_BUILDS})
+endif(NOT MSVC)
 
 target_include_directories(qgis_server SYSTEM PUBLIC
   ${CMAKE_SOURCE_DIR}/external/inja