26 files changed, 989 insertions, 47 deletions

diff --git a/.gitignore b/.gitignore
index 4a8a9cb..6310280 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,6 +1,7 @@
 drumgizmo/
 build/
 ctor
+ctor.exe
 *.a
 *.o
 *.d
diff --git a/.gitmodules b/.gitmodules
index c765825..383739b 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -4,3 +4,9 @@
 [submodule "test/uunit"]
 	path = test/uunit
 	url = git://git.drumgizmo.org/uunit.git
+[submodule "getopt-for-windows"]
+	path = getopt-for-windows
+	url = https://github.com/Chunde/getopt-for-windows.git
+[submodule "json"]
+	path = json
+	url = https://github.com/nlohmann/json.git
diff --git a/Jenkinsfile b/Jenkinsfile
index a558359..cc659ab 100644
--- a/Jenkinsfile
+++ b/Jenkinsfile
@@ -5,6 +5,31 @@ pipeline {
 		{
 			parallel {
 				////////////////////////////////////////////////////
+				stage('Windows msvc') {
+					agent { label 'win10 && msvc' }
+					environment
+					{
+						VSDEVCMD="C:\\Program Files (x86)\\Microsoft Visual Studio\\2022\\BuildTools\\Common7\\Tools\\VsDevCmd.bat"
+					}
+					steps {
+						echo 'Cleaning workspace ...'
+						bat 'git clean -d -x -f'
+						dir ('build/test') {
+							writeFile file:'dummy', text:''
+						}
+						bat '"%VSDEVCMD%" && bootstrap.bat && ctor.exe'
+						echo 'Testing (msvc) ...'
+						bat 'ctor.exe check'
+					}
+					post {
+						always {
+							xunit(thresholds: [ skipped(failureThreshold: '0'),
+							                    failed(failureThreshold: '0') ],
+							      tools: [ CppUnit(pattern: 'build/test/*.xml') ])
+						}
+					}
+				}
+				////////////////////////////////////////////////////
 				stage('MacOSX clang') {
 					agent { label 'macos' }
 					steps {
diff --git a/bootstrap.bat b/bootstrap.bat
new file mode 100644
index 0000000..3802663
--- /dev/null
+++ b/bootstrap.bat
@@ -0,0 +1,25 @@
+@echo off
+
+set CXX=cl.exe
+set CC=cl.exe
+set AR=lib.exe
+set LD=link.exe
+
+echo Bootstrapping...
+%CXX% /nologo /MT /std:c++20 /D_X86_ /EHsc /Isrc /Fo:build\ ctor.cc src\bootstrap.cc /link /out:ctor.exe
+@if %errorlevel% neq 0 exit /b %errorlevel%
+
+ctor.exe
+@if %errorlevel% neq 0 exit /b %errorlevel%
+
+%CXX% /nologo /std:c++20 /D_X86_ /EHsc /Isrc /Fo:build\ ctor.cc /c
+@if %errorlevel% neq 0 exit /b %errorlevel%
+%CXX% /nologo /std:c++20 /D_X86_ /EHsc /Isrc /Fo:build\test\ test\ctor.cc /c
+@if %errorlevel% neq 0 exit /b %errorlevel%
+%LD% /nologo build\libctor.lib build\ctor.obj build\test\ctor.obj /subsystem:console /out:ctor.exe
+@if %errorlevel% neq 0 exit /b %errorlevel%
+
+ctor.exe configure --ctor-includedir=src --ctor-libdir=build
+@if %errorlevel% neq 0 exit /b %errorlevel%
+
+@echo Done. Now run ctor.exe to (re)build.
diff --git a/clrun.sh b/clrun.sh
new file mode 100755
index 0000000..d0f3cbb
--- /dev/null
+++ b/clrun.sh
@@ -0,0 +1,27 @@
+#!/bin/bash
+#set -e
+#set -x
+export WINEDEBUG=-all
+
+rm -f ~/.wine/drive_c/number
+
+export BASE='C:\Program Files (x86)\Microsoft Visual Studio\2019\BuildTools\VC\Tools\MSVC\14.29.30133'
+export ONECORELIB="$BASE\lib\onecore\x86"
+export WINEPATH="$BASE\bin\Hostx86\x86"
+export INCLUDE="$BASE\include"
+export UCRT="C:\Program Files (x86)\Windows Kits\10\Include\10.0.19041.0\ucrt"
+export UCRTLIB="C:\Program Files (x86)\Windows Kits\10\Lib\10.0.19041.0\ucrt\x86"
+export UM="C:\Program Files (x86)\Windows Kits\10\Include\10.0.19041.0\um"
+export UMLIB="C:\Program Files (x86)\Windows Kits\10\Lib\10.0.19041.0\um\x86"
+export SHARED="C:\Program Files (x86)\Windows Kits\10\Include\10.0.19041.0\shared"
+
+export CL="/I\"$BASE\include\" /I\"$UCRT\" /I\"$UM\" /I\"$SHARED\" /link /LIBPATH:\"$UMLIB\" /LIBPATH:\"$ONECORELIB\" /LIBPATH:\"$UCRTLIB\""
+export LINK="/LIBPATH:\"$UMLIB\" /LIBPATH:\"$ONECORELIB\" /LIBPATH:\"$UCRTLIB\""
+export LIB="/LIBPATH:\"$UMLIB\" /LIBPATH:\"$ONECORELIB\" /LIBPATH:\"$UCRTLIB\""
+
+
+
+#wine ctor.exe
+
+$*
+
diff --git a/ctor.cc b/ctor.cc
index 67b1465..7f49255 100644
--- a/ctor.cc
+++ b/ctor.cc
@@ -31,8 +31,23 @@ ctor::build_configurations ctorConfigs(const ctor::settings& settings)
 				"src/tools.cc",
 				"src/util.cc",
 				"src/unittest.cc",
+				{ctor::toolchain::msvc, "getopt-for-windows/getopt.c"},
 			},
 			.flags = {
+				.cflags = {
+					"-O3",
+//					"-g",
+//					"-Wall",
+//					"-Wconversion",
+//					"-Wextra",
+					//"-Werror",
+					"-Isrc",
+					{ctor::toolchain::msvc, ctor::c_opt::custom, "/Igetopt-for-windows"},
+					{ctor::toolchain::msvc, ctor::c_opt::custom, "/D_X86_"},
+					{ctor::toolchain::msvc, ctor::c_opt::custom, "/EHsc"},
+					{ctor::toolchain::msvc, ctor::c_opt::custom, "/external:W0"},
+					{ctor::toolchain::msvc, ctor::c_opt::custom, "/D_CRT_SECURE_NO_WARNINGS"},
+				},
 				.cxxflags = {
 					"-std=c++20",
 					"-O3",
@@ -44,6 +59,13 @@ ctor::build_configurations ctorConfigs(const ctor::settings& settings)
 					"-Wconversion",
 //					"-Wnrvo",
 					"-Isrc",
+					"-Ijson/include",
+					{ctor::toolchain::msvc, ctor::cxx_opt::custom, "/Igetopt-for-windows"},
+					{ctor::toolchain::msvc, ctor::cxx_opt::custom, "/D_X86_"},
+					{ctor::toolchain::msvc, ctor::cxx_opt::custom, "/EHsc"},
+					{ctor::toolchain::msvc, ctor::cxx_opt::custom, "/external:W0"},
+					{ctor::toolchain::msvc, ctor::cxx_opt::custom, "/D_CRT_SECURE_NO_WARNINGS"},
+					{ctor::toolchain::msvc, ctor::cxx_opt::custom, "/Dstrdup=_strdup"},
 				},
 			},
 		}
diff --git a/getopt-for-windows b/getopt-for-windows
new file mode 160000
+Subproject 76fe2df86f84771775fd2f1a641a09adbce28df
diff --git a/json b/json
new file mode 160000
+Subproject 6be4e8560023098fdb6d2047e6e6e5bc5dd5287
diff --git a/src/configure.cc b/src/configure.cc
index a43152f..b52824e 100644
--- a/src/configure.cc
+++ b/src/configure.cc
@@ -8,6 +8,8 @@
 #include <fstream>
 #include <optional>
 #include <span>
+#include <vector>
+#include <deque>
 
 #include <getoptpp/getoptpp.hpp>
 
@@ -25,7 +27,11 @@ const std::filesystem::path configHeaderFile("config.h");
 std::map<std::string, std::string> external_includedir;
 std::map<std::string, std::string> external_libdir;
 
+#if !defined(_WIN32)
 const ctor::configuration& __attribute__((weak)) ctor::get_configuration()
+#else
+const ctor::configuration& default_get_configuration()
+#endif
 {
 	static ctor::configuration cfg;
 	static bool initialised{false};
@@ -44,6 +50,14 @@ const ctor::configuration& __attribute__((weak)) ctor::get_configuration()
 	}
 	return cfg;
 }
+#if defined(_WIN32)
+// Hack to make ctor::get_configuration "weak" linked
+// See:
+//   https://stackoverflow.com/questions/2290587/gcc-style-weak-linking-in-visual-studio
+// and
+//   https://stackoverflow.com/questions/11849853/how-to-list-functions-present-in-object-file
+#pragma comment(linker, "/alternatename:?get_configuration@ctor@@YAABUconfiguration@1@XZ=?default_get_configuration@@YAABUconfiguration@ctor@@XZ")
+#endif
 
 namespace ctor {
 std::optional<std::string> includedir;
@@ -100,11 +114,47 @@ std::string ctor::configuration::get(const std::string& key,
 		return ctor::conf_values[key];
 	}
 
-	if(has(key))
+	if(tools.find(key) != tools.end())
 	{
 		return tools.at(key);
 	}
 
+	if(key == ctor::cfg::build_cxx)
+	{
+		auto e = std::getenv("CXX");
+		if(e)
+		{
+			return e;
+		}
+	}
+
+	if(key == ctor::cfg::build_cc)
+	{
+		auto e = std::getenv("CC");
+		if(e)
+		{
+			return e;
+		}
+	}
+
+	if(key == ctor::cfg::build_ld)
+	{
+		auto e = std::getenv("LD");
+		if(e)
+		{
+			return e;
+		}
+	}
+
+	if(key == ctor::cfg::build_ar)
+	{
+		auto e = std::getenv("AR");
+		if(e)
+		{
+			return e;
+		}
+	}
+
 	return default_value;
 }
 
@@ -162,6 +212,9 @@ std::ostream& operator<<(std::ostream& stream, const ctor::toolchain& toolchain)
 	case ctor::toolchain::gcc:
 		stream << "ctor::toolchain::gcc";
 		break;
+	case ctor::toolchain::msvc:
+		stream << "ctor::toolchain::msvc";
+		break;
 	case ctor::toolchain::clang:
 		stream << "ctor::toolchain::clang";
 		break;
@@ -676,6 +729,7 @@ int regenerateCache(ctor::settings& settings,
 	{
 		ctor::conf_values[ctor::cfg::builddir] = builddir;
 	}
+
 	ctor::conf_values[ctor::cfg::host_cxx] = host_cxx;
 	ctor::conf_values[ctor::cfg::build_cxx] = build_cxx;
 
@@ -906,6 +960,31 @@ int configure(const ctor::settings& global_settings, int argc, char* argv[])
 		env["PATH"] = path_env;
 	}
 
+	// Env vars for msvc
+	auto cl_env = getenv("CL");
+	if(cl_env)
+	{
+		env["CL"] = cl_env;
+	}
+
+	auto lib_env = getenv("LIB");
+	if(lib_env)
+	{
+		env["LIB"] = lib_env;
+	}
+
+	auto link_env = getenv("LINK");
+	if(link_env)
+	{
+		env["LINK"] = link_env;
+	}
+
+	auto include_env = getenv("INCLUDE");
+	if(include_env)
+	{
+		env["INCLUDE"] = include_env;
+	}
+
 	auto ret = regenerateCache(settings, args_span[0], args, env);
 	if(ret != 0)
 	{
diff --git a/src/ctor.h b/src/ctor.h
index 9c6fcf6..4deee98 100644
--- a/src/ctor.h
+++ b/src/ctor.h
@@ -59,6 +59,7 @@ enum class toolchain
 	none,
 	gcc,
 	clang,
+	msvc,
 };
 
 struct source
diff --git a/src/deps.cc b/src/deps.cc
index 9400b35..599be8c 100644
--- a/src/deps.cc
+++ b/src/deps.cc
@@ -5,6 +5,8 @@
 
 #include "util.h"
 
+#include <nlohmann/json.hpp>
+
 #include <fstream>
 
 namespace {
@@ -94,6 +96,74 @@ std::vector<std::string> readDepsMake(const std::string& dep_file)
 
 	return output;
 }
+
+// https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2022/p1689r5.html
+// https://devblogs.microsoft.com/cppblog/introducing-source-dependency-reporting-with-msvc-in-visual-studio-2019-version-16-7/
+/* Format examples:
+{
+    "Version": "1.1",
+    "Data": {
+        "Source": "z:\\home\\deva\\docs\\c\\ctor\\src\\libctor.cc",
+        "ProvidedModule": "",
+        "Includes": [
+            "c:\\program files (x86)\\microsoft visual studio\\2019\\buildtools\\vc\\tools\\msvc\\14.29.30133\\include\\vector",
+            "c:\\program files (x86)\\microsoft visual studio\\2019\\buildtools\\vc\\tools\\msvc\\14.29.30133\\include\\yvals_core.h",
+            "c:\\program files (x86)\\microsoft visual studio\\2019\\buildtools\\vc\\tools\\msvc\\14.29.30133\\include\\vcruntime.h",
+.
+.
+.
+            "z:\\home\\deva\\docs\\c\\ctor\\src\\unittest.h"
+        ],
+        "ImportedModules": [],
+        "ImportedHeaderUnits": []
+    }
+}
+*/
+/*
+{
+    "Version": "1.2",
+    "Data": {
+        "Source": "c:\\jenkins\\workspace\\ctor-linux64\\src\\build.cc",
+        "ProvidedModule": "",
+        "Includes": [
+            "c:\\jenkins\\workspace\\ctor-linux64\\src\\build.h",
+            "c:\\program files (x86)\\microsoft visual studio\\2022\\buildtools\\vc\\tools\\msvc\\14.42.34433\\include\\string",
+            "c:\\program files (x86)\\microsoft visual studio\\2022\\buildtools\\vc\\tools\\msvc\\14.42.34433\\include\\yvals_core.h",
+.
+.
+.
+            "c:\\program files (x86)\\microsoft visual studio\\2022\\buildtools\\vc\\tools\\msvc\\14.42.34433\\include\\iostream"
+        ],
+        "ImportedModules": [],
+        "ImportedHeaderUnits": []
+    }
+}
+*/
+
+std::vector<std::string> readDepsJson(const std::string& dep_file)
+{
+	std::ifstream stream(dep_file);
+	auto json = nlohmann::json::parse(stream);
+	for(const auto& [key, value] : json.items())
+	{
+		if(key == "Data" && value.is_object())
+		{
+			for(const auto& [inner_key, inner_value] : value.items())
+			{
+				if(inner_key == "Includes" && inner_value.is_array())
+				{
+					std::vector<std::string> deps;
+					for(const auto& dep : inner_value)
+					{
+						deps.emplace_back(dep);
+					}
+					return deps;
+				}
+			}
+		}
+	}
+	return {};
+}
 }
 
 std::vector<std::string> readDeps(const std::string& dep_file,
@@ -110,6 +180,10 @@ std::vector<std::string> readDeps(const std::string& dep_file,
 	case ctor::toolchain::none:
 		return {};
 
+	// json based:
+	case ctor::toolchain::msvc:
+		return readDepsJson(dep_file);
+
 	// makefile .d file based:
 	case ctor::toolchain::gcc:
 	case ctor::toolchain::clang:
diff --git a/src/execute.cc b/src/execute.cc
index c050732..4ed274f 100644
--- a/src/execute.cc
+++ b/src/execute.cc
@@ -6,12 +6,24 @@
 #include "ctor.h"
 #include "pointerlist.h"
 
-#include <unistd.h>
-#include <cstring>
-#include <sys/types.h>
-#include <sys/wait.h>
-#include <spawn.h>
+#if !defined(_WIN32)
+	#include <unistd.h>
+	#include <sys/types.h>
+	#include <sys/wait.h>
+	#include <spawn.h>
+	extern char **environ;
+#else
+	#define WINDOWS_LEAN_AND_MEAN
+	#include <windows.h>
+	#undef max
+	#include <thread>
+#endif
+
 #include <iostream>
+#include <cstring>
+#include <vector>
+#include <deque>
+#include <filesystem>
 
 /*
 https://blog.famzah.net/2009/11/20/a-much-faster-popen-and-system-implementation-for-linux/
@@ -23,7 +35,7 @@ https://stackoverflow.com/questions/4259629/what-is-the-difference-between-fork-
 
 namespace
 {
-
+#if !defined(_WIN32)
 int parent_waitpid(pid_t pid)
 {
 	int status{};
@@ -61,9 +73,80 @@ int parent_waitpid(pid_t pid)
 	// Should never happen...
 	return 1;
 }
-} // namespace ::
+#endif //_WIN32
+
+#if defined(_WIN32)
+std::string getLastErrorAsString()
+{
+	DWORD errorMessageID = ::GetLastError();
+	if(errorMessageID == 0)
+	{
+		return {};
+	}
+
+	LPSTR message_buffer{};
+	auto size = FormatMessageA(FORMAT_MESSAGE_ALLOCATE_BUFFER |
+	                           FORMAT_MESSAGE_FROM_SYSTEM |
+	                           FORMAT_MESSAGE_IGNORE_INSERTS,
+	                           nullptr,
+	                           errorMessageID, MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
+	                           (LPSTR)&message_buffer, 0, nullptr);
+
+	std::string message(message_buffer, size);
+	LocalFree(message_buffer);
+	return message;
+}
+
+int moveSelf(const ctor::settings& settings)
+{
+	int cnt{0};
+	char source[MAX_PATH];
+	HMODULE module = GetModuleHandle(0);
+	GetModuleFileNameA(module, source, MAX_PATH);
+
+	while(true)
+	{
+		if(cnt > 10) // If we need to try more than 10 times something is wrong
+		{
+			return 1;
+		}
+
+		std::filesystem::path tmp_file = settings.builddir;
+		tmp_file /= "tmp";
+		std::string target = tmp_file.string() + "-" + std::to_string(cnt);
+		if(MoveFileA(source, target.data()))
+		{
+			break; // success
+		}
+
+		auto err = GetLastError();
+		if(err == ERROR_ALREADY_EXISTS)
+		{
+			if(DeleteFileA(target.data()))
+			{
+				continue; // Try again
+			}
+
+			err = GetLastError();
+			if(err != ERROR_ACCESS_DENIED)
+			{
+				std::cerr << "Could not delete file\n";
+				return err;
+			}
 
-extern char **environ; // see 'man environ'
+			cnt++;
+			continue; // Increment and try again
+		}
+		else
+		{
+			std::cerr << "Could not move file\n";
+			return err;
+		}
+	}
+	return 0;
+}
+#endif // _WIN32
+} // namespace ::
 
 int execute(const ctor::settings& settings,
             const std::string& command,
@@ -98,11 +181,13 @@ int execute(const ctor::settings& settings,
 		std::cout << cmd << std::endl;
 	}
 
+#if !defined(_WIN32)
+
 #if 1
 	auto pid = vfork();
 	if(pid == 0)
 	{
-		EnvMap envmap((const char**)environ);
+		EnvMap envmap(environ);
 		for(const auto& [key, value] : env)
 		{
 			envmap.insert(key + "=" + value);
@@ -120,15 +205,16 @@ int execute(const ctor::settings& settings,
 	}
 	return parent_waitpid(pid);
 #elif 0
-	pid_t pid;
-	std::vector<std::string> venv;
+	pid_t pid{};
+	EnvMap envmap(environ);
 	for(const auto& [key, value] : env)
 	{
-		venv.push_back(key + "=" + value);
+		envmap.insert(key + "=" + value);
 	}
-	Env penv(venv);
+
+	auto [_, envv] = envmap.get();
 	if(posix_spawn(&pid, command.data(), nullptr, nullptr,
-	               (char**)argv.data(), penv.data()))
+	               (char**)argv.data(), const_cast<char* const *>(envv)))
 	{
 		return 1;
 	}
@@ -138,5 +224,139 @@ int execute(const ctor::settings& settings,
 	return system(cmd.data());
 #endif
 
+#else // _WIN32
+	if(terminate)
+	{
+		auto ret = moveSelf(settings);
+		if(ret != 0)
+		{
+			return ret;
+		}
+	}
+
+	auto env_strings = GetEnvironmentStrings();
+	EnvMap envmap(env_strings);
+	FreeEnvironmentStrings(env_strings);
+	for(const auto& [key, value] : env)
+	{
+		envmap.insert(key + "=" + value);
+	}
+
+	// TODO: Use SetDllDirectory(...) to set DLL search directory?
+
+	SECURITY_ATTRIBUTES security_attr;
+	// Set the bInheritHandle flag so pipe handles are inherited.
+	security_attr.nLength = sizeof(SECURITY_ATTRIBUTES);
+	security_attr.bInheritHandle = TRUE;
+	security_attr.lpSecurityDescriptor = nullptr;
+
+	HANDLE stream_in_read{};
+	HANDLE stream_in_write{};
+	HANDLE stream_out_read{};
+	HANDLE stream_out_write{};
+
+	if(!CreatePipe(&stream_out_read, &stream_out_write, &security_attr, 0))
+	{
+		std::cout << "Error CreatePipe (out): " << getLastErrorAsString() << "\n";
+	}
+
+	if(!SetHandleInformation(stream_out_read, HANDLE_FLAG_INHERIT, 0))
+	{
+		std::cout << "Error - SetHandleInformation (out): " << getLastErrorAsString() << "\n";
+	}
+
+	// Create a pipe for the child process's STDIN.
+	if(!CreatePipe(&stream_in_read, &stream_in_write, &security_attr, 0))
+	{
+		std::cout << "Error CreatePipe (in): " << getLastErrorAsString() << "\n";
+	}
+
+	// Ensure the write handle to the pipe for STDIN is not inherited.
+	if(!SetHandleInformation(stream_in_write, HANDLE_FLAG_INHERIT, 0))
+	{
+		std::cout << "Error - SetHandleInformation (in): " << getLastErrorAsString() << "\n";
+	}
+
+	STARTUPINFO si{};
+	si.hStdInput = GetStdHandle(((DWORD)-10));//STD_INPUT_HANDLE
+	si.hStdOutput = stream_out_write;
+	si.hStdError = stream_out_write;
+	si.dwFlags |= STARTF_USESTDHANDLES;
+
+	PROCESS_INFORMATION pi{};
+
+	si.cb = sizeof(si);
+
+	if(!CreateProcess(nullptr,           // lpApplicationName
+	                  (char*)cmd.data(), // lpCommandLine
+	                  nullptr,           // lpProcessAttributes
+	                  nullptr,           // lpThreadAttributes
+	                  TRUE,              // bInheritHandles
+	                  INHERIT_PARENT_AFFINITY |
+	                  0x00000200 | // CREATE_NEW_PROCESS_GROUP
+	                  0,                 // dwCreationFlags
+	                  envmap.stringify().data(),    // lpEnvironment
+	                  nullptr,           // lpCurrentDirectory
+	                  &si,               // lpStartupInfo
+	                  &pi))              // lpProcessInformation
+	{
+		std::cout << "Could not execute " << command << ": " <<
+			getLastErrorAsString() << "\n";
+		return 1;
+	}
+
+	int ignore_lines{};
+	std::filesystem::path cmd_path{command};
+	if(cmd_path.filename() == "cl.exe")
+	{
+		// Ignore first line, avoiding the annoying msvc compiler of printing the filename
+		// of the file that is being compiled
+		ignore_lines = 1;
+	}
+
+	std::atomic<bool> running{true};
+	auto parent_waitpid = std::thread([&](){
+		WaitForSingleObject(pi.hProcess, INFINITE);
+		CloseHandle(stream_out_write);
+		CloseHandle(stream_in_read);
+		running.store(false);
+	});
+
+	CHAR buf[1024];
+	while(running.load())
+	{
+		if(WaitForSingleObject(stream_out_read, 0) != WAIT_OBJECT_0)
+		{
+			Sleep(1);
+			continue;
+		}
+		DWORD read_bytes{};
+		auto res = ReadFile(stream_out_read, buf, sizeof(buf), &read_bytes, nullptr);
+		if(res != TRUE || read_bytes == 0)
+		{
+			break;
+		}
+		std::string str;
+		str.append(buf, read_bytes);
+		if(ignore_lines == 0)
+		{
+			std::cout << str << std::flush;
+		}
+		if(str.find('\n') != std::string::npos)
+		{
+			ignore_lines = std::max(0, ignore_lines - 1);
+		}
+	}
+
+	DWORD exit_code{};
+	GetExitCodeProcess(pi.hProcess, &exit_code);
+	parent_waitpid.join();
+
+	CloseHandle(pi.hProcess);
+	CloseHandle(pi.hThread);
+
+	return exit_code;
+#endif // _WIN32
+
 	return 1;
 }
diff --git a/src/rebuild.cc b/src/rebuild.cc
index a2b7ddd..9a3fca0 100644
--- a/src/rebuild.cc
+++ b/src/rebuild.cc
@@ -38,7 +38,10 @@ int reg(ctor::build_configurations (*cb)(const ctor::settings&),
 	{
 		auto pwd = std::filesystem::current_path();
 		auto rel = std::filesystem::relative(loc, pwd);
-		configFiles[numConfigFiles].file = strdup(rel.string().data()); // NOTE: This intentionally leaks memory
+		auto str = rel.string();
+		auto file = new char[str.size() + 1];
+		strncpy(file, str.data(), str.size() + 1);
+		configFiles[numConfigFiles].file = file; // NOTE: This intentionally leaks memory
 	}
 	else
 	{
@@ -169,6 +172,8 @@ bool recompileCheck(const ctor::settings& global_settings, int argc, char* argv[
 	config.flags.cxxflags.emplace_back(ctor::cxx_opt::optimization, "3");
 	config.flags.cxxflags.emplace_back(ctor::cxx_opt::cpp_std, "c++20");
 
+	config.flags.cxxflags.push_back({ctor::toolchain::msvc, ctor::cxx_opt::custom, "/EHsc"});
+
 	const auto& c = ctor::get_configuration();
 	if(c.has(ctor::cfg::ctor_includedir))
 	{
@@ -180,9 +185,13 @@ bool recompileCheck(const ctor::settings& global_settings, int argc, char* argv[
 		config.flags.ldflags.emplace_back(ctor::ld_opt::library_path,
 		                                  c.get(ctor::cfg::ctor_libdir));
 	}
-	config.flags.ldflags.emplace_back(ctor::ld_opt::link, "ctor");
+	config.flags.ldflags.emplace_back(ctor::toolchain::msvc, ctor::ld_opt::link, "libctor.lib");
+	config.flags.ldflags.emplace_back(ctor::toolchain::gcc, ctor::ld_opt::link, "ctor");
+	config.flags.ldflags.emplace_back(ctor::toolchain::clang, ctor::ld_opt::link, "ctor");
 	config.flags.ldflags.emplace_back(ctor::ld_opt::threads);
 
+	config.flags.ldflags.push_back({ctor::toolchain::msvc, ctor::ld_opt::custom, "/subsystem:console"});
+
 	ctor::settings settings{global_settings};
 	settings.verbose = -1; // Make check completely silent.
 
diff --git a/src/task_ar.cc b/src/task_ar.cc
index 3b45cc2..0365d51 100644
--- a/src/task_ar.cc
+++ b/src/task_ar.cc
@@ -93,6 +93,8 @@ int TaskAR::runInner()
 	append(args, ar_option(toolchain, ctor::ar_opt::add_index));
 	append(args, ar_option(toolchain, ctor::ar_opt::create));
 	append(args, ar_option(toolchain, ctor::ar_opt::output, targetFile().string()));
+	append(args, to_strings(toolchain, {ctor::toolchain::msvc, ctor::ar_opt::custom, "/nologo"}));
+
 	for(const auto& task : getDependsTasks())
 	{
 		args.push_back(task->targetFile().string());
diff --git a/src/task_cc.cc b/src/task_cc.cc
index 9628455..b300cd6 100644
--- a/src/task_cc.cc
+++ b/src/task_cc.cc
@@ -305,12 +305,14 @@ std::vector<std::string> TaskCC::flags() const
 		{
 			append(flags, to_strings(toolchain, flag));
 		}
+		append(flags, to_strings(toolchain, {ctor::toolchain::msvc, ctor::c_opt::custom, "/nologo"}));
 		return flags;
 	case ctor::language::cpp:
 		for(const auto& flag : config.flags.cxxflags)
 		{
 			append(flags, to_strings(toolchain, flag));
 		}
+		append(flags, to_strings(toolchain, {ctor::toolchain::msvc, ctor::cxx_opt::custom, "/nologo"}));
 		return flags;
 	default:
 		std::cerr << "Unknown CC target type\n";
diff --git a/src/task_ld.cc b/src/task_ld.cc
index 03745be..af71bbb 100644
--- a/src/task_ld.cc
+++ b/src/task_ld.cc
@@ -115,6 +115,7 @@ int TaskLD::runInner()
 	}
 
 	append(args, ld_option(toolchain, ctor::ld_opt::output, targetFile().string()));
+	append(args, to_strings(toolchain, {ctor::toolchain::msvc, ctor::ld_opt::custom, "/nologo"}));
 
 	{ // Write flags to file.
 		std::ofstream flagsStream(flagsFile);
@@ -129,11 +130,28 @@ int TaskLD::runInner()
 
 	auto tool = compiler();
 	const auto& cfg = ctor::get_configuration();
-	auto ldflags = cfg.getenv("LDFLAGS");
-	if(!ldflags.empty())
+	if(toolchain == ctor::toolchain::gcc ||
+	   toolchain == ctor::toolchain::clang)
 	{
-		append(args, ld_option(toolchain, ctor::ld_opt::custom, ldflags));
+		auto ldflags = cfg.getenv("LDFLAGS");
+		if(!ldflags.empty())
+		{
+			append(args, ld_option(toolchain, ctor::ld_opt::custom, ldflags));
+		}
 	}
+	else // msvc
+	{
+		switch(outputSystem())
+		{
+		case ctor::output_system::host:
+			tool = cfg.get(ctor::cfg::host_ld, "/usr/bin/ld");
+			break;
+		case ctor::output_system::build:
+			tool = cfg.get(ctor::cfg::build_ld, "/usr/bin/ld");
+			break;
+		}
+	}
+
 	auto res = execute(settings, tool, args, cfg.env, is_self);
 	if(res != 0)
 	{
diff --git a/src/task_so.cc b/src/task_so.cc
index 92aeefe..db07c53 100644
--- a/src/task_so.cc
+++ b/src/task_so.cc
@@ -93,6 +93,8 @@ int TaskSO::runInner()
 
 	append(args, ld_option(toolchain, ctor::ld_opt::output, targetFile().string()));
 
+	append(args, to_strings(toolchain, {ctor::toolchain::msvc, ctor::ld_opt::custom, "/nologo"}));
+
 	for(const auto& task : getDependsTasks())
 	{
 		args.push_back(task->targetFile().string());
diff --git a/src/tools.cc b/src/tools.cc
index dfabdff..1a539be 100644
--- a/src/tools.cc
+++ b/src/tools.cc
@@ -6,6 +6,7 @@
 #include <filesystem>
 #include <iostream>
 #include <sstream>
+#include <algorithm>
 #include <array>
 
 #include <cassert>
@@ -13,6 +14,11 @@
 
 #include "util.h"
 
+#if defined(_WIN32)
+#define popen _popen
+#define pclose _pclose
+#endif
+
 std::ostream& operator<<(std::ostream& stream, const ctor::c_opt& opt)
 {
 	// Adding to this enum should also imply adding to the unit-tests below
@@ -129,6 +135,10 @@ ctor::toolchain getToolChain(const std::string& compiler)
 	{
 		return ctor::toolchain::gcc;
 	}
+	else if(to_lower(cc_cmd).find("cl") != std::string::npos)
+	{
+		return ctor::toolchain::msvc;
+	}
 
 	std::cerr << "Unsupported output system.\n";
 	return ctor::toolchain::gcc;
@@ -154,12 +164,256 @@ ctor::toolchain getToolChain(ctor::output_system system)
 		return getToolChain(cfg.get(ctor::cfg::build_cxx, "g++"));
 	}
 }
+namespace msvc {
+std::string get_arch([[maybe_unused]] ctor::output_system system)
+{
+	return "windows";
+}
+
+ctor::arch get_arch([[maybe_unused]] const std::string& str)
+{
+	return ctor::arch::windows;
+}
+
+ctor::c_flag c_option(const std::string& flag)
+{
+	if(flag.starts_with("/I"))
+	{
+		std::string path = flag.substr(2);
+		path.erase(0, path.find_first_not_of(' '));
+		return { ctor::c_opt::include_path, path };
+	}
+
+	return { ctor::c_opt::custom, flag };
+}
+
+ctor::cxx_flag cxx_option(const std::string& flag)
+{
+	if(flag.starts_with("/I"))
+	{
+		std::string path = flag.substr(2);
+		path.erase(0, path.find_first_not_of(' '));
+		return { ctor::cxx_opt::include_path, path };
+	}
+
+	return { ctor::cxx_opt::custom, flag };
+}
+
+ctor::ld_flag ld_option(const std::string& flag)
+{
+	if(flag.starts_with("/L"))
+	{
+		std::string path = flag.substr(2);
+		path.erase(0, path.find_first_not_of(' '));
+		return { ctor::ld_opt::library_path, path };
+	}
+
+	return { ctor::ld_opt::custom, flag };
+}
+
+ctor::ar_flag ar_option(const std::string& flag)
+{
+	return { ctor::ar_opt::custom, flag };
+}
+
+std::vector<std::string> cxx_option(ctor::cxx_opt opt, const std::string& arg,
+                                    const std::string& arg2)
+{
+	switch(opt)
+	{
+	case ctor::cxx_opt::output:
+		return {"/Fo\"" + arg + "\""};
+	case ctor::cxx_opt::debug:
+		return {"/DEBUG"};
+	case ctor::cxx_opt::warn_all:
+		return {"/W4"};
+	case ctor::cxx_opt::warn_conversion:
+		return {"/W4"}; // TODO: This is incorrect
+	case ctor::cxx_opt::warn_shadow:
+		return {"/W4"}; // TODO: This is incorrect
+	case ctor::cxx_opt::warn_extra:
+		return {"/W4"}; // TODO: This is incorrect
+	case ctor::cxx_opt::warnings_as_errors:
+		return {"/WX"};
+	case ctor::cxx_opt::generate_dep_tree:
+		return {"/sourceDependencies", arg};
+	case ctor::cxx_opt::no_link:
+		return {"/c"};
+	case ctor::cxx_opt::include_path:
+		return {"/I" + arg};
+	case ctor::cxx_opt::cpp_std:
+		return {"/std:" + arg};
+	case ctor::cxx_opt::optimization:
+		{
+			int o{0};
+			try
+			{
+				o = std::stoi(arg);
+				o = std::clamp(o, 0, 2);
+			}
+			catch(...)
+			{
+				// bad number?
+			}
+			return {"/O" + std::to_string(o)};
+		}
+	case ctor::cxx_opt::position_independent_code:
+		return {}; // TODO?
+	case ctor::cxx_opt::position_independent_executable:
+		return {}; // TODO?
+	case ctor::cxx_opt::define:
+		if(!arg2.empty())
+		{
+			return {"/D" + arg + "=" + esc(arg2)};
+		}
+		else
+		{
+			return {"/D" + arg};
+		}
+	case ctor::cxx_opt::custom:
+		return {arg};
+	}
+
+	std::cerr << "Unsupported compiler option.\n";
+	return {};
+}
+
+std::vector<std::string> c_option(ctor::c_opt opt, const std::string& arg,
+                                  const std::string& arg2)
+{
+	switch(opt)
+	{
+	case ctor::c_opt::output:
+		return {"/Fo\"" + arg + "\""};
+	case ctor::c_opt::debug:
+		return {"/DEBUG"};
+	case ctor::c_opt::warn_all:
+		return {"/W4"};
+	case ctor::c_opt::warn_conversion:
+		return {"/W4"}; // TODO: This is incorrect
+	case ctor::c_opt::warn_shadow:
+		return {"/W4"}; // TODO: This is incorrect
+	case ctor::c_opt::warn_extra:
+		return {"/W4"}; // TODO: This is incorrect
+	case ctor::c_opt::warnings_as_errors:
+		return {"/WX"};
+	case ctor::c_opt::generate_dep_tree:
+		return {"/sourceDependencies", arg};
+	case ctor::c_opt::no_link:
+		return {"/c"};
+	case ctor::c_opt::include_path:
+		return {"/I" + arg};
+	case ctor::c_opt::c_std:
+		return {"/std:" + arg};
+	case ctor::c_opt::optimization:
+		{
+			int o{0};
+			try
+			{
+				o = std::stoi(arg);
+				o = std::clamp(o, 0, 2);
+			}
+			catch(...)
+			{
+				// bad number?
+			}
+			return {"/O" + std::to_string(o)};
+		}
+	case ctor::c_opt::position_independent_code:
+		return {}; // TODO?
+	case ctor::c_opt::position_independent_executable:
+		return {}; // TODO?
+	case ctor::c_opt::define:
+		if(!arg2.empty())
+		{
+			return {"/D" + arg + "=" + esc(arg2)};
+		}
+		else
+		{
+			return {"/D" + arg};
+		}
+	case ctor::c_opt::custom:
+		return {arg};
+	}
+
+	std::cerr << "Unsupported compiler option.\n";
+	return {};
+}
+
+std::vector<std::string> ld_option(ctor::ld_opt opt, const std::string& arg,
+                                   [[maybe_unused]]const std::string& arg2)
+{
+	switch(opt)
+	{
+	case ctor::ld_opt::output:
+		return {"/out:" + arg + ""};
+	case ctor::ld_opt::warn_all:
+		return {"/Wall"};
+	case ctor::ld_opt::warnings_as_errors:
+		return {"/WX"};
+	case ctor::ld_opt::library_path:
+		return {"/LIBPATH:\""+arg+"\""};
+	case ctor::ld_opt::link:
+		return {arg}; // TODO?
+	case ctor::ld_opt::cpp_std:
+		return {"/std:" + arg};
+	case ctor::ld_opt::build_shared:
+		return {}; // TODO?
+	case ctor::ld_opt::threads:
+		return {}; // TODO?
+	case ctor::ld_opt::position_independent_code:
+		return {}; // TODO?
+	case ctor::ld_opt::position_independent_executable:
+		return {}; // TODO?
+	case ctor::ld_opt::custom:
+		return {arg};
+	}
+
+	std::cerr << "Unsupported compiler option.\n";
+	return {};
+}
+
+std::vector<std::string> ar_option(ctor::ar_opt opt, const std::string& arg,
+                                   [[maybe_unused]]const std::string& arg2)
+{
+	switch(opt)
+	{
+	case ctor::ar_opt::replace:
+		return {};
+	case ctor::ar_opt::add_index:
+		return {};
+	case ctor::ar_opt::create:
+		return {};
+	case ctor::ar_opt::output:
+		return {"/out:" + arg};
+	case ctor::ar_opt::custom:
+		return {arg};
+	}
+
+	std::cerr << "Unsupported compiler option.\n";
+	return {};
+}
+
+std::vector<std::string> asm_option(ctor::asm_opt opt, const std::string& arg,
+                                    [[maybe_unused]]const std::string& arg2)
+{
+	switch(opt)
+	{
+	case ctor::asm_opt::custom:
+		return {arg};
+	}
+
+	std::cerr << "Unsupported compiler option.\n";
+	return {};
+}
+} // msvc::
+
 
 namespace gcc {
-std::string get_arch(ctor::output_system system)
+std::string get_arch([[maybe_unused]] ctor::output_system system)
 {
+	std::string arch;
 	std::string cmd;
-
 	const auto& c = ctor::get_configuration();
 	switch(system)
 	{
@@ -180,7 +434,6 @@ std::string get_arch(ctor::output_system system)
 		return {};//ctor::arch::unknown;
 	}
 
-	std::string arch;
 	while(!feof(pipe))
 	{
 		constexpr auto buffer_size{1024};
@@ -571,6 +824,8 @@ std::string get_arch(ctor::output_system system)
 	case ctor::toolchain::clang:
 	case ctor::toolchain::gcc:
 		return gcc::get_arch(system);
+	case ctor::toolchain::msvc:
+		return msvc::get_arch(system);
 	case ctor::toolchain::any:
 	case ctor::toolchain::none:
 		break;
@@ -586,6 +841,8 @@ ctor::arch get_arch(ctor::output_system system, const std::string& str)
 	case ctor::toolchain::clang:
 	case ctor::toolchain::gcc:
 		return gcc::get_arch(str);
+	case ctor::toolchain::msvc:
+		return msvc::get_arch(str);
 	case ctor::toolchain::any:
 	case ctor::toolchain::none:
 		break;
@@ -603,6 +860,8 @@ std::vector<std::string> c_option(ctor::toolchain toolchain,
 	case ctor::toolchain::gcc:
 	case ctor::toolchain::clang:
 		return gcc::c_option(opt, arg, arg2);
+	case ctor::toolchain::msvc:
+		return msvc::c_option(opt, arg, arg2);
 	case ctor::toolchain::any:
 		{
 			std::ostringstream ss;
@@ -636,6 +895,8 @@ std::vector<std::string> cxx_option(ctor::toolchain toolchain,
 	case ctor::toolchain::gcc:
 	case ctor::toolchain::clang:
 		return gcc::cxx_option(opt, arg, arg2);
+	case ctor::toolchain::msvc:
+		return msvc::cxx_option(opt, arg, arg2);
 	case ctor::toolchain::any:
 		{
 			std::ostringstream ss;
@@ -669,6 +930,8 @@ std::vector<std::string> ld_option(ctor::toolchain toolchain,
 	case ctor::toolchain::gcc:
 	case ctor::toolchain::clang:
 		return gcc::ld_option(opt, arg, arg2);
+	case ctor::toolchain::msvc:
+		return msvc::ld_option(opt, arg, arg2);
 	case ctor::toolchain::any:
 		{
 			std::ostringstream ss;
@@ -702,6 +965,8 @@ std::vector<std::string> ar_option(ctor::toolchain toolchain,
 	case ctor::toolchain::gcc:
 	case ctor::toolchain::clang:
 		return gcc::ar_option(opt, arg, arg2);
+	case ctor::toolchain::msvc:
+		return msvc::ar_option(opt, arg, arg2);
 	case ctor::toolchain::any:
 		{
 			std::ostringstream ss;
@@ -735,6 +1000,8 @@ std::vector<std::string> asm_option(ctor::toolchain toolchain,
 	case ctor::toolchain::gcc:
 	case ctor::toolchain::clang:
 		return gcc::asm_option(opt, arg, arg2);
+	case ctor::toolchain::msvc:
+		return msvc::asm_option(opt, arg, arg2);
 	case ctor::toolchain::any:
 		{
 			std::ostringstream ss;
@@ -766,6 +1033,8 @@ ctor::c_flag c_option(const std::string& flag, ctor::toolchain toolchain)
 	case ctor::toolchain::gcc:
 	case ctor::toolchain::clang:
 		return gcc::c_option(flag);
+	case ctor::toolchain::msvc:
+		return msvc::c_option(flag);
 	case ctor::toolchain::any:
 	case ctor::toolchain::none:
 		break;
@@ -781,6 +1050,8 @@ ctor::cxx_flag cxx_option(const std::string& flag, ctor::toolchain toolchain)
 	case ctor::toolchain::gcc:
 	case ctor::toolchain::clang:
 		return gcc::cxx_option(flag);
+	case ctor::toolchain::msvc:
+		return msvc::cxx_option(flag);
 	case ctor::toolchain::any:
 	case ctor::toolchain::none:
 		break;
@@ -796,6 +1067,8 @@ ctor::ld_flag ld_option(const std::string& flag, ctor::toolchain toolchain)
 	case ctor::toolchain::gcc:
 	case ctor::toolchain::clang:
 		return gcc::ld_option(flag);
+	case ctor::toolchain::msvc:
+		return msvc::ld_option(flag);
 	case ctor::toolchain::any:
 	case ctor::toolchain::none:
 		break;
@@ -811,6 +1084,8 @@ ctor::ar_flag ar_option(const std::string& flag, ctor::toolchain toolchain)
 	case ctor::toolchain::gcc:
 	case ctor::toolchain::clang:
 		return gcc::ar_option(flag);
+	case ctor::toolchain::msvc:
+		return msvc::ar_option(flag);
 	case ctor::toolchain::any:
 	case ctor::toolchain::none:
 		break;
@@ -825,6 +1100,7 @@ ctor::asm_flag asm_option(const std::string& flag, ctor::toolchain toolchain)
 	{
 	case ctor::toolchain::gcc:
 	case ctor::toolchain::clang:
+	case ctor::toolchain::msvc:
 	case ctor::toolchain::any:
 	case ctor::toolchain::none:
 		break;
@@ -908,10 +1184,11 @@ ctor::toolchain guess_toolchain(const std::string& opt)
 		return ctor::toolchain::gcc;
 	}
 
-	//if(opt[0] == '/')
-	//{
-	//	return ctor::toolchain::msvc;
-	//}
+	if(opt[0] == '/')
+	{
+		return ctor::toolchain::msvc;
+	}
+
 	return ctor::toolchain::any;
 }
 }
@@ -982,8 +1259,8 @@ ctor::target_type target_type_from_extension(ctor::toolchain toolchain,
 		}
 	}
 
-	if(toolchain == ctor::toolchain::any// ||
-	   //toolchain == ctor::toolchain::msvc ||
+	if(toolchain == ctor::toolchain::any ||
+	   toolchain == ctor::toolchain::msvc// ||
 	   //toolchain == ctor::toolchain::mingw ||
 		)
 	{
diff --git a/src/util.cc b/src/util.cc
index 6fc650a..20dea71 100644
--- a/src/util.cc
+++ b/src/util.cc
@@ -8,10 +8,17 @@
 #include <algorithm>
 #include <sstream>
 
+namespace {
+char to_lower_c(char ch)
+{
+	return static_cast<char>(::tolower(ch));
+}
+}
+
 std::string to_lower(const std::string& str)
 {
 	std::string out{str};
-	std::transform(out.begin(), out.end(), out.begin(), ::tolower);
+	std::transform(out.begin(), out.end(), out.begin(), to_lower_c);
 	return out;
 }
 
@@ -20,13 +27,18 @@ std::string readFile(const std::string& fileName)
 	std::ifstream ifs(fileName.c_str(),
 	                  std::ios::in | std::ios::binary | std::ios::ate);
 
-	std::ifstream::pos_type fileSize = ifs.tellg();
+	auto tell = ifs.tellg();
+	if(tell < 0)
+	{
+		return {};
+	}
+	auto fileSize = static_cast<std::size_t>(tell);
 	ifs.seekg(0, std::ios::beg);
 
-	std::vector<char> bytes(static_cast<std::size_t>(fileSize));
-	ifs.read(bytes.data(), fileSize);
+	std::vector<char> bytes(fileSize);
+	ifs.read(bytes.data(), static_cast<long>(bytes.size()));
 
-	return {bytes.data(), static_cast<std::size_t>(fileSize)};
+	return { bytes.data(), bytes.size() };
 }
 
 ctor::language languageFromExtension(const std::filesystem::path& file)
@@ -71,7 +83,7 @@ namespace
 {
 bool isClean(char c)
 {
-	return c != '.' && c != '/';
+	return c != '.' && c != '/' && c != '\\';
 }
 }
 
@@ -170,15 +182,36 @@ std::string locate(const std::string& prog,
 		}
 	}
 
+	if(std::filesystem::exists(program + ".exe"))
+	{
+		if(check_executable(program + ".exe"))
+		{
+			return program + ".exe";
+		}
+	}
+
 	for(const auto& path_str : paths)
 	{
 		std::filesystem::path path(path_str);
-		auto prog_path = path / program;
-		if(std::filesystem::exists(prog_path))
 		{
-			if(check_executable(prog_path))
+			auto prog_path = path / program;
+			if(std::filesystem::exists(prog_path))
+			{
+				if(check_executable(prog_path))
+				{
+					return prog_path.string();
+				}
+			}
+		}
+
+		{
+			auto prog_path = path / (program + ".exe");
+			if(std::filesystem::exists(prog_path))
 			{
-				return prog_path.string();
+				if(check_executable(prog_path))
+				{
+					return prog_path.string();
+				}
 			}
 		}
 	}
diff --git a/test/ctor.cc b/test/ctor.cc
index b7bcc6d..fa53802 100644
--- a/test/ctor.cc
+++ b/test/ctor.cc
@@ -23,6 +23,8 @@ ctor::build_configurations ctorTestConfigs(const ctor::settings& settings)
 					"-std=c++20", "-O3", "-Wall", "-Werror",
 					"-I../src", "-Iuunit",
 					"-DOUTPUT=\"argsplit\"",
+					{ctor::toolchain::msvc, ctor::cxx_opt::custom, "/EHsc"},
+					{ctor::toolchain::msvc, ctor::cxx_opt::custom, "/D_CRT_SECURE_NO_WARNINGS"},
 				},
 			},
 		},
@@ -40,6 +42,8 @@ ctor::build_configurations ctorTestConfigs(const ctor::settings& settings)
 					"-std=c++20", "-O3", "-Wall", "-Werror",
 					"-I../src", "-Iuunit",
 					"-DOUTPUT=\"pointerlist\"",
+					{ctor::toolchain::msvc, ctor::cxx_opt::custom, "/EHsc"},
+					{ctor::toolchain::msvc, ctor::cxx_opt::custom, "/D_CRT_SECURE_NO_WARNINGS"},
 				},
 			},
 		},
@@ -58,7 +62,10 @@ ctor::build_configurations ctorTestConfigs(const ctor::settings& settings)
 				.cxxflags = {
 					"-std=c++20", "-O3", "-Wall", "-Werror",
 					"-I../src", "-Iuunit",
+					"-I../json/include",
 					"-DOUTPUT=\"deps\"",
+					{ctor::toolchain::msvc, ctor::cxx_opt::custom, "/EHsc"},
+					{ctor::toolchain::msvc, ctor::cxx_opt::custom, "/D_CRT_SECURE_NO_WARNINGS"},
 				},
 			},
 		},
@@ -72,6 +79,8 @@ ctor::build_configurations ctorTestConfigs(const ctor::settings& settings)
 			.flags = {
 				.cxxflags = {
 					"-std=c++20", "-O3", "-Wall", "-Werror",
+					{ctor::toolchain::msvc, ctor::cxx_opt::custom, "/EHsc"},
+					{ctor::toolchain::msvc, ctor::cxx_opt::custom, "/D_CRT_SECURE_NO_WARNINGS"},
 				},
 			},
 		},
@@ -92,6 +101,8 @@ ctor::build_configurations ctorTestConfigs(const ctor::settings& settings)
 					"-std=c++20", "-O3", "-Wall", "-Werror",
 					"-I../src", "-Iuunit",
 					"-DOUTPUT=\"execute\"",
+					{ctor::toolchain::msvc, ctor::cxx_opt::custom, "/EHsc"},
+					{ctor::toolchain::msvc, ctor::cxx_opt::custom, "/D_CRT_SECURE_NO_WARNINGS"},
 				},
 				.ldflags = { "-pthread" },
 			},
@@ -110,6 +121,8 @@ ctor::build_configurations ctorTestConfigs(const ctor::settings& settings)
 					"-std=c++20", "-O3", "-Wall", "-Werror",
 					"-I../src", "-Iuunit",
 					"-DOUTPUT=\"tasks\"",
+					{ctor::toolchain::msvc, ctor::cxx_opt::custom, "/EHsc"},
+					{ctor::toolchain::msvc, ctor::cxx_opt::custom, "/D_CRT_SECURE_NO_WARNINGS"},
 				},
 				.ldflags = { "-pthread" },
 			},
@@ -128,6 +141,8 @@ ctor::build_configurations ctorTestConfigs(const ctor::settings& settings)
 					"-std=c++20", "-O3", "-Wall", "-Werror",
 					"-I../src", "-Iuunit",
 					"-DOUTPUT=\"cycle\"",
+					{ctor::toolchain::msvc, ctor::cxx_opt::custom, "/EHsc"},
+					{ctor::toolchain::msvc, ctor::cxx_opt::custom, "/D_CRT_SECURE_NO_WARNINGS"},
 				},
 				.ldflags = { "-pthread" },
 			},
@@ -146,6 +161,8 @@ ctor::build_configurations ctorTestConfigs(const ctor::settings& settings)
 					"-std=c++20", "-O3", "-Wall", "-Werror",
 					"-I../src", "-Iuunit",
 					"-DOUTPUT=\"source_type\"",
+					{ctor::toolchain::msvc, ctor::cxx_opt::custom, "/EHsc"},
+					{ctor::toolchain::msvc, ctor::cxx_opt::custom, "/D_CRT_SECURE_NO_WARNINGS"},
 				},
 				.ldflags = { "-pthread" },
 			},
@@ -166,6 +183,8 @@ ctor::build_configurations ctorTestConfigs(const ctor::settings& settings)
 					"-std=c++20", "-O3", "-Wall", "-Werror",
 					"-I../src", "-Iuunit",
 					"-DOUTPUT=\"tools\"",
+					{ctor::toolchain::msvc, ctor::cxx_opt::custom, "/EHsc"},
+					{ctor::toolchain::msvc, ctor::cxx_opt::custom, "/D_CRT_SECURE_NO_WARNINGS"},
 				},
 			},
 		},
@@ -190,11 +209,33 @@ ctor::build_configurations ctorTestConfigs(const ctor::settings& settings)
 				"../src/tools.cc",
 				"../src/util.cc",
 				"../src/externals_manual.cc",
+				{ctor::toolchain::msvc, "../getopt-for-windows/getopt.c"},
 			},
 			.flags = {
+				.cflags = {
+					"-O3",
+//					"-g",
+//					"-Wall",
+//					"-Wconversion",
+//					"-Wextra",
+					//"-Werror",
+					"-I../src",
+					{ctor::toolchain::msvc, ctor::c_opt::custom, "/I../getopt-for-windows"},
+					{ctor::toolchain::msvc, ctor::c_opt::custom, "/D_X86_"},
+					{ctor::toolchain::msvc, ctor::c_opt::custom, "/EHsc"},
+					{ctor::toolchain::msvc, ctor::c_opt::custom, "/external:W0"},
+					{ctor::toolchain::msvc, ctor::c_opt::custom, "/D_CRT_SECURE_NO_WARNINGS"},
+				},
 				.cxxflags = {
 					"-std=c++20", "-O3", "-Wall", "-Werror",
 					"-I../src",
+					"-I../json/include",
+					{ctor::toolchain::msvc, ctor::cxx_opt::custom, "/I../getopt-for-windows"},
+					{ctor::toolchain::msvc, ctor::cxx_opt::custom, "/D_X86_"},
+					{ctor::toolchain::msvc, ctor::cxx_opt::custom, "/EHsc"},
+					{ctor::toolchain::msvc, ctor::cxx_opt::custom, "/external:W0"},
+					{ctor::toolchain::msvc, ctor::cxx_opt::custom, "/D_CRT_SECURE_NO_WARNINGS"},
+					{ctor::toolchain::msvc, ctor::cxx_opt::custom, "/Dstrdup=_strdup"},
 				},
 				.ldflags = { "-pthread" },
 			},
diff --git a/test/execute_test.cc b/test/execute_test.cc
index 722b6ea..6a376f8 100644
--- a/test/execute_test.cc
+++ b/test/execute_test.cc
@@ -36,11 +36,23 @@ public:
 		value = execute(s, "no-such-binary", {}, {}, false);
 		uASSERT_EQUAL(1, value);
 		value = execute(s, cmd, {"segfault"}, {}, false);
+#if !defined(_WIN32)
 		uASSERT_EQUAL(11, value);
+#else
+		uASSERT_EQUAL(3, value);
+#endif
 		value = execute(s, cmd, {"throw"}, {}, false);
+#if !defined(_WIN32)
 		uASSERT_EQUAL(6, value);
+#else
+		uASSERT_EQUAL(-1073740791, value);
+#endif
 		value = execute(s, cmd, {"abort"}, {}, false);
+#if !defined(_WIN32)
 		uASSERT_EQUAL(6, value);
+#else
+		uASSERT_EQUAL(-1073740791, value);
+#endif
 	}
 
 	void env()
diff --git a/test/source_type_test.cc b/test/source_type_test.cc
index 288f1e5..657260e 100644
--- a/test/source_type_test.cc
+++ b/test/source_type_test.cc
@@ -26,6 +26,14 @@ std::ostream& operator<<(std::ostream& stream, const ctor::language& lang)
 	return stream;
 }
 
+const ctor::configuration& ctor::get_configuration()
+{
+	static ctor::configuration cfg{};
+	cfg.build_toolchain = ctor::toolchain::gcc;
+	cfg.build_arch = ctor::arch::unix;
+	return cfg;
+}
+
 class TestableTaskCC
 	: public TaskCC
 {
diff --git a/test/suite/test.sh b/test/suite/test.sh
index 97d2551..d57580f 100755
--- a/test/suite/test.sh
+++ b/test/suite/test.sh
@@ -1,4 +1,6 @@
 #!/bin/bash
+#set -x
+
 : ${CXX:=g++}
 : ${CTORDIR:=../../build}
 : ${BUILDDIR:=build}
diff --git a/test/testprog.cc b/test/testprog.cc
index 93edc3f..18c2c74 100644
--- a/test/testprog.cc
+++ b/test/testprog.cc
@@ -5,6 +5,14 @@
 
 extern char **environ;
 
+#if defined(_WIN32)
+#define WINDOWS_LEAN_AND_MEAN
+#include <windows.h>
+#undef max
+#else
+extern char **environ; // see 'man environ'
+#endif
+
 int main(int argc, const char* argv[])
 {
 	if(argc < 2)
@@ -20,11 +28,41 @@ int main(int argc, const char* argv[])
 		{
 			return 0;
 		}
+
 		std::ofstream ostrm(argv[2], std::ios::binary);
+		if(ostrm.bad())
+		{
+			std::cout << "Error: Could not write to " << argv[2] << "\n";
+		}
+#if defined(_WIN32)
+		auto env_strings = GetEnvironmentStrings();
+		const char* ptr = env_strings;
+		std::string env;
+		while(true)
+		{
+			if(*ptr == '\0')
+			{
+				if(env.empty())
+				{
+					// no more
+					break;
+				}
+				ostrm << env << "\n";
+				env.clear();
+				++ptr;
+				continue;
+			}
+
+			env += *ptr;
+			++ptr;
+		}
+		FreeEnvironmentStrings(env_strings);
+#else
 		for(auto current = environ; *current; ++current)
 		{
 			ostrm << (*current) << "\n";
 		}
+#endif
 	}
 
 	if(cmd == "retval")
diff --git a/test/tmpfile.h b/test/tmpfile.h
index 5d114d0..a5d4043 100644
--- a/test/tmpfile.h
+++ b/test/tmpfile.h
@@ -4,7 +4,7 @@
 #pragma once
 
 #include <cstdlib>
-#include <unistd.h>
+#include <cstring>
 
 #ifdef _WIN32
 #define WIN32_LEAN_AND_MEAN
@@ -12,6 +12,9 @@
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <fcntl.h>
+#include <io.h>
+#else
+#include <unistd.h>
 #endif
 
 struct tmp_file
@@ -19,23 +22,35 @@ struct tmp_file
 	tmp_file(const std::string& data = {})
 	{
 		int fd;
+		auto tmp_dir = std::filesystem::temp_directory_path();
+		auto tmp_file_template = tmp_dir / "ctor_tmp_file-XXXXXX";
+		filename = tmp_file_template.string();
+		auto buf = new char[filename.size() + 2];
+		memcpy(buf, filename.data(), filename.size() + 1);
 #ifdef _WIN32
-		char templ[] = "ctor_tmp_file-XXXXXX"; // buffer for filename
-		_mktemp_s(templ, sizeof(templ));
-		fd = open(templ, O_CREAT | O_RDWR);
+		_mktemp_s(buf, filename.size() + 2);
+		filename = buf;
+		fd = _open(filename.data(), O_CREAT | O_RDWR, _S_IWRITE);
+		auto sz = _write(fd, data.data(), data.size());
+		(void)sz;
+		_close(fd);
 #else
-		char templ[] = "/tmp/ctor_tmp_file-XXXXXX"; // buffer for filename
-		fd = mkstemp(templ);
-#endif
-		filename = templ;
+		fd = mkstemp(buf);
+		filename = buf;
 		auto sz = write(fd, data.data(), data.size());
 		(void)sz;
 		close(fd);
+#endif
+		delete[] buf;
 	}
 
 	~tmp_file()
 	{
+#ifdef _WIN32
+		_unlink(filename.data());
+#else
 		unlink(filename.data());
+#endif
 	}
 
 	const std::string& get() const
diff --git a/test/tools_test.cc b/test/tools_test.cc
index 5ae04c3..15270b3 100644
--- a/test/tools_test.cc
+++ b/test/tools_test.cc
@@ -22,6 +22,9 @@ std::ostream& operator<<(std::ostream& stream, const ctor::toolchain& toolchain)
 	case ctor::toolchain::clang:
 		stream << "ctor::toolchain::clang";
 		break;
+	case ctor::toolchain::msvc:
+		stream << "ctor::toolchain::msvc";
+		break;
 	}
 	return stream;
 }