Fixed MSVC support

source/HotReload/CMakeLists.txt

@@ -12,3 +12,16 @@ if(NOT WIN32)
 	# (nonexistent, for a static lib) link step.
 	target_link_libraries(hotreload_lib PUBLIC ${CMAKE_DL_LIBS})
 endif()
+
+if(MSVC)
+	# UnDecorateSymbolName (Demangle.cpp) lives in dbghelp.lib, which --
+	# unlike kernel32/user32 -- MSVC does not link by default. Without
+	# this, the final link fails with an undefined symbol for it;
+	# found via an actual Windows build of this library, not just
+	# documentation. PUBLIC for the same reason as CMAKE_DL_LIBS above.
+	# Guarded on MSVC (true for both real cl.exe and clang-cl, and
+	# false for MinGW) rather than WIN32, since MinGW's build of
+	# Demangle.cpp takes the __GNUC__/__cxa_demangle branch instead and
+	# never needs dbghelp at all.
+	target_link_libraries(hotreload_lib PUBLIC dbghelp)
+endif()

source/HotReload/README.md

@@ -283,17 +283,32 @@ export-table reader in `SymbolTable.cpp`.
   `_ZN9CppWidget4tickEi` lookup string was derived from a native GCC
   build but also worked unmodified against this MinGW/Wine build and
   the separate native Clang build).
-- **MSVC itself was not run anywhere in this process** -- there is no
-  Windows machine or MSVC install available in the environment this
-  was built in. The MSVC-specific code (`/hotpatch`,
-  `IMAGE_EXPORT_DIRECTORY` parsing, `VirtualProtect`,
-  `FlushInstructionCache`) is written directly against Microsoft's
-  documented structures and behavior, and the equivalent PE-reading
-  code was compiled clean against real `<windows.h>` headers via
-  MinGW, but treat the MSVC path as unverified until you've built it
-  on an actual Windows box. If it doesn't work, `SymbolTable.cpp`'s
-  PE branch and `cmake/HotReload.cmake`'s `/hotpatch` branch are the
-  two places to look first.
+- **MSVC was never run directly in the environment that built this
+  library** -- there is no Windows machine or MSVC install available
+  there. It has, since, been built and live-tested on real MSVC by
+  someone using this library, surfacing four real fixes now folded
+  in: `windows.h` must be included before `dbghelp.h` (the reverse
+  order fails to compile -- `dbghelp.h` assumes types like `HANDLE`
+  are already defined rather than including their own headers),
+  `NOMINMAX` needs defining before `windows.h` in every file that
+  includes it (`SymbolTable.cpp` concretely needs this -- without it,
+  windows.h's own `min`/`max` macros substitute into that file's
+  `std::max`/`std::min` calls and it fails to compile), MSVC needs
+  `dbghelp.lib` linked explicitly for `UnDecorateSymbolName`
+  (`source/HotReload/CMakeLists.txt` now does this whenever
+  `MSVC` is true, which also covers `clang-cl`), and
+  `source/examples/HotReloadLiveDemo`'s reload-retry logic needed
+  widening (see that example's own file for why). The MSVC-specific
+  code (`/hotpatch`, `IMAGE_EXPORT_DIRECTORY` parsing,
+  `VirtualProtect`, `FlushInstructionCache`) was written directly
+  against Microsoft's documented structures and behavior before any
+  of that feedback existed, and the equivalent PE-reading code was
+  separately compiled clean against real `<windows.h>` headers via
+  MinGW -- between the two, treat it as real-world-checked now, not
+  merely reasoned through, though obviously with less first-hand
+  confidence than everything that was directly, repeatedly run in
+  this project's own development loop (native GCC/Clang, ARM64 under
+  QEMU, MinGW under Wine).
 - **32-bit ARM was not implemented at all**, deliberately: it's the
   one architecture in this list where getting it wrong is easy and
   getting it verified is hard. Its instructions are either 4 bytes

source/HotReload/src/MemoryProtection.cpp

@@ -3,6 +3,13 @@
 #include <cstdint>
 
 #if defined(_WIN32)
+	// NOMINMAX: prevents windows.h from defining min/max macros that
+	// would otherwise clash with std::min/std::max and anything else
+	// named min/max in this translation unit -- found via an actual
+	// Windows build/run of this library, not just documentation.
+	#ifndef NOMINMAX
+		#define NOMINMAX
+	#endif
 	#include <windows.h>
 #else
 	#include <sys/mman.h>

source/HotReload/src/ModuleHandle.cpp

@@ -3,6 +3,12 @@
 #include <string>
 
 #if defined(_WIN32)
+	// NOMINMAX: see MemoryProtection.cpp's identical comment -- same
+	// windows.h, same reason, needed in every translation unit that
+	// includes it, not just once for the library as a whole.
+	#ifndef NOMINMAX
+		#define NOMINMAX
+	#endif
 	#include <windows.h>
 #else
 	#include <dlfcn.h>

source/HotReload/src/SymbolTable.cpp

@@ -35,6 +35,16 @@ namespace hot_reload::detail
 	// headers just gets added directly to loadedBase.
 	// ---------------------------------------------------------------
 
+	// NOMINMAX matters concretely in this exact file, not just as a
+	// defensive habit: without it, windows.h's own min/max macros
+	// substitute into the std::max/std::min calls a few lines below
+	// (the preprocessor sees the bare token max after std::, not the
+	// qualified name, and expands it regardless) and the file fails to
+	// compile on MSVC. Found via an actual Windows build/run of this
+	// library, not just documentation.
+	#ifndef NOMINMAX
+		#define NOMINMAX
+	#endif
 	#include <windows.h>
 
 	namespace

source/HotReload/src/c-api/Demangle.cpp

@@ -29,8 +29,27 @@
 	// beyond just this function.
 	#include <cxxabi.h>
 #elif defined(_MSC_VER)
-	#include <dbghelp.h>
+	// windows.h must come first: dbghelp.h uses types (HANDLE, DWORD,
+	// BOOL, ...) it assumes are already defined rather than including
+	// their defining headers itself -- reversing this order fails to
+	// compile. NOMINMAX prevents windows.h from defining min/max
+	// macros that would otherwise clash with std::min/std::max and
+	// anything else named min/max in this translation unit. Both
+	// fixes below came from an actual Windows build/run of this
+	// library, not just documentation -- see README.md's toolchain
+	// verification notes.
+	#ifndef NOMINMAX
+		#define NOMINMAX
+	#endif
 	#include <windows.h>
+	#include <dbghelp.h>
+	// Belt-and-suspenders for anyone building this file outside this
+	// project's own CMake (source/HotReload/CMakeLists.txt links
+	// dbghelp explicitly for every MSVC-family build, which is the
+	// primary fix and the one actually required -- confirmed directly
+	// that omitting it leaves UnDecorateSymbolName undefined at link
+	// time regardless of this pragma).
+	#pragma comment(lib, "dbghelp.lib")
 #endif
 
 extern "C"
@@ -61,10 +80,12 @@ extern "C"
 			// DbgHelp) -- but DbgHelp as a whole is documented as not
 			// thread-safe, so serialize calls to this function
 			// yourself if you call it from more than one thread.
-			// Written against Microsoft's documented behavior; unlike
-			// most of this library, this specific function was not
-			// exercised on real Windows -- see README.md's toolchain
-			// verification notes.
+			// Exercised on a real Windows build (see README.md's
+			// toolchain verification notes) -- getting the
+			// windows.h/dbghelp.h include order and NOMINMAX right
+			// (see the #include block above) and linking dbghelp
+			// explicitly (source/HotReload/CMakeLists.txt) were both
+			// needed to get here.
 			char buffer[2048];
 			if (UnDecorateSymbolName(name, buffer, sizeof(buffer), UNDNAME_COMPLETE) != 0)
 			{

source/examples/HotReloadLiveDemo/Host/Main.cpp

@@ -147,25 +147,51 @@ int main(int argc, char** argv)
 		auto currentWriteTime = std::filesystem::last_write_time(pluginPath, currentTimeStatus);
 		if (!currentTimeStatus && currentWriteTime != lastWriteTime)
 		{
-			// A short settle delay for a linker that might still be
-			// mid-write on a slower filesystem -- not load-bearing for
-			// correctness either way: a reload attempted too early
-			// just fails cleanly (hot_reload_reload() never disturbs
-			// the running version on failure) and gets retried next
-			// iteration, since lastWriteTime below is only updated on
-			// success.
-			std::this_thread::sleep_for(std::chrono::milliseconds(150));
-
 			std::printf("\n-- change detected in %s, reloading --\n", pluginPath.c_str());
-			HotReloadStatus status = hot_reload_reload(ctx, "live", pluginPath.c_str());
+
+			// A few quick retries, not just one settle delay: on
+			// Windows specifically, a rebuilt DLL can report its new
+			// write time a moment before it's actually fully readable
+			// -- observed directly (live-tested by someone building
+			// this feature): the file had genuinely finished building
+			// and hot-reloaded correctly a moment later, but the
+			// FIRST attempt, right after the write-time change was
+			// noticed, still failed. Retrying a handful of times
+			// before reporting failure absorbs that gap; a single
+			// fixed delay guessed from Linux's own timing was not
+			// enough. Not load-bearing for correctness either way --
+			// a reload attempted too early just fails cleanly
+			// (hot_reload_reload() never disturbs the running version
+			// on failure) -- this only changes whether a purely
+			// transient timing gap gets reported to you as a scary
+			// but spurious failure.
+			constexpr int maxAttempts = 5;
+			HotReloadStatus status = HOT_RELOAD_ERROR_LOAD_FAILED;
+			for (int attempt = 1; attempt <= maxAttempts; ++attempt)
+			{
+				std::this_thread::sleep_for(std::chrono::milliseconds(150 * attempt));
+				status = hot_reload_reload(ctx, "live", pluginPath.c_str());
+				if (status == HOT_RELOAD_OK)
+				{
+					break;
+				}
+			}
+
 			if (status == HOT_RELOAD_OK)
 			{
 				lastWriteTime = currentWriteTime;
 			}
 			else
 			{
-				std::printf("-- reload failed: %s -- still running the previous version; fix and save again --\n",
-					hot_reload_last_error(ctx));
+				std::printf(
+					"-- reload failed after %d attempts: %s -- still running the previous version; fix and "
+					"save again --\n",
+					maxAttempts, hot_reload_last_error(ctx));
+				// lastWriteTime deliberately NOT updated here: the
+				// next iteration of this loop sees the same "changed"
+				// timestamp and starts a fresh round of retries, in
+				// case the file becomes available even later than
+				// this round waited for.
 			}
 			std::printf("\n");
 		}

source/examples/HotReloadLiveDemo/Plugin/src/LivePlugin.cpp

@@ -42,11 +42,13 @@
 #include "hot_reload/hot_reload.h"
 
 #include <cstdio>
+#include <iostream>
 
 extern "C" HOT_RELOAD_EXPORT int live_tick(int frame)
 {
 	int multiplier = 2; // <- try changing this
 	int value = frame * multiplier;
-	std::printf("  live_tick(%d) -> %d\n", frame, value);
+	std::printf("  live_tick (%d) -> %d\n", frame, value);
+	std::cout.flush();
 	return value;
 }