ASDAlexander77 · Oct 5, 2026 · Oct 5, 2026 · Oct 5, 2026
diff --git a/README.md b/README.md
@@ -30,6 +30,37 @@ repo:
   `scripts\build_tslang_runtime_<debug|release>_x86.bat` in `TypeScriptCompiler`, which
   puts it in `__build\tslang-runtime\<debug|release>\x86\`.
 
+### Android
+
+On a Windows host, with the Android NDK (tested with r30) in `ANDROID_NDK_HOME`:
+
+```
+scripts\build_android.bat                        # arm64-v8a and x86_64, release and debug, all models
+scripts\build_android.bat arm64-v8a release gc   # just that one
+```
+
+This builds for API level 29 (the lowest with `timespec_get`) into
+`__build\android\<abi>\defaultlib\{lib,dll}\<debug|release>\<gc|rc|none>\`, one complete tree
+per ABI. It needs a `tslang.exe` that can target Android (`TOOL_PATH`, default: the compiler's
+release build tree). Android has no libcurl, so HTTP is `src\wrappers\http_stub.cpp`: `fetch()`
+throws. The `.so` links `libc++_shared.so`, which the app ships.
+
+The collector and the async runtime come from the compiler repo:
+`scripts\build_gc_release_android.bat` and `scripts\build_tslang_runtime_release_android.bat`.
+A program is compiled and then linked with the NDK, for example for arm64-v8a under `gc`:
+
+```
+tslang --emit=obj -mtriple=aarch64-linux-android29 -relocation-model=pic --opt -mm=gc ^
+    --default-lib-path=__build\android\arm64-v8a app.ts -o app.o
+aarch64-linux-android29-clang++ -pie -static-libstdc++ app.o ^
+    -L__build\android\arm64-v8a\defaultlib\lib\release\gc ^
+    -L<TypeScriptCompiler>\3rdParty\gc\android\arm64-v8a\release\lib ^
+    -L<TypeScriptCompiler>\__build\tslang-runtime\release\android\arm64-v8a ^
+    -lTypeScriptDefaultLib -lgc -lTypeScriptAsyncRuntime -lm -ldl -o app
+```
+
+(`-lgc` only under `gc`.) `tslang --emit=exe` does not link for Android yet.
+
 ## Testing
 
 ```

diff --git a/scripts/build_android.bat b/scripts/build_android.bat
@@ -0,0 +1,124 @@
+@rem Builds the default library for Android (API 29) on a Windows host, the Android counterpart of
+@rem scripts/build.sh.
+@rem
+@rem   scripts\build_android.bat [abi] [release|debug] [gc|rc|none]
+@rem
+@rem   abi    arm64-v8a | x86_64   (default: both)
+@rem   mode   release | debug      (default: both)
+@rem   model  gc | rc | none       (default: all three - see build.sh on why each needs its own)
+@rem
+@rem Needs:
+@rem   ANDROID_NDK_HOME  the Android NDK (tested with r30), e.g. C:\Android\android-ndk-r30
+@rem   TOOL_PATH         the directory holding a tslang.exe with Android support (#506); defaults
+@rem                     to the compiler's release build tree next to this repository
+@rem
+@rem Output, one complete default-library tree per ABI (a program compiled for that ABI takes
+@rem --default-lib-path=__build\android\<abi>, the directory holding defaultlib\):
+@rem   __build\android\<abi>\defaultlib\lib\<mode>\<model>\libTypeScriptDefaultLib.a
+@rem   __build\android\<abi>\defaultlib\dll\<mode>\<model>\libTypeScriptDefaultLib.so
+@rem   __build\android\<abi>\defaultlib\*.d.ts ...
+@rem
+@rem Differences from build.sh:
+@rem - HTTP is src\wrappers\http_stub.cpp, not http_linux.cpp: libcurl is not part of Android, so
+@rem   fetch() throws instead. The archive is therefore the library itself, with no linker script
+@rem   pulling in -lcurl.
+@rem - Everything is position independent, the archive too: Android executables must be PIE.
+@rem - The .so links the NDK's default C++ library, libc++_shared.so, which the app ships (Android
+@rem   allows one C++ runtime per app). GC_* stay undefined in it on purpose, as in build.sh.
+@rem
+@rem API 29 is the floor: lib.linux.ts calls timespec_get, which Bionic has from 29 on.
+@echo off
+setlocal
+
+if "%ANDROID_NDK_HOME%"=="" (
+    echo ANDROID_NDK_HOME is not set: point it at the Android NDK, e.g. C:\Android\android-ndk-r30
+    exit /b 1
+)
+
+set ABI=%~1
+set MODE=%~2
+set MM=%~3
+
+if "%ABI%"=="" (
+    call "%~f0" arm64-v8a "%MODE%" "%MM%" || exit /b 1
+    call "%~f0" x86_64 "%MODE%" "%MM%" || exit /b 1
+    exit /b 0
+)
+if "%MODE%"=="" (
+    call "%~f0" %ABI% release "%MM%" || exit /b 1
+    call "%~f0" %ABI% debug "%MM%" || exit /b 1
+    exit /b 0
+)
+if "%MM%"=="" (
+    call "%~f0" %ABI% %MODE% gc || exit /b 1
+    call "%~f0" %ABI% %MODE% rc || exit /b 1
+    call "%~f0" %ABI% %MODE% none || exit /b 1
+    exit /b 0
+)
+
+if "%ABI%"=="arm64-v8a" (
+    set TRIPLE=aarch64-linux-android29
+) else if "%ABI%"=="x86_64" (
+    set TRIPLE=x86_64-linux-android29
+) else (
+    echo unknown ABI "%ABI%": arm64-v8a or x86_64
+    exit /b 1
+)
+
+if "%MODE%"=="release" (
+    set DBG=--opt --opt_level=3
+    set DBG_CXX=-O3
+) else if "%MODE%"=="debug" (
+    set DBG=--di --opt_level=0
+    set DBG_CXX=-g
+) else (
+    echo unknown mode "%MODE%": release or debug
+    exit /b 1
+)
+
+if not "%MM%"=="gc" if not "%MM%"=="rc" if not "%MM%"=="none" (
+    echo unknown memory model "%MM%": gc, rc or none
+    exit /b 1
+)
+
+set ROOT=%~dp0..
+if "%TOOL_PATH%"=="" set TOOL_PATH=%ROOT%\..\TypeScriptCompiler\__build\tslang\windows-msbuild-2026-release\bin
+set TSLANG="%TOOL_PATH%\tslang.exe"
+if not exist %TSLANG% (
+    echo tslang.exe not found in "%TOOL_PATH%": set TOOL_PATH
+    exit /b 1
+)
+
+set NDK_BIN=%ANDROID_NDK_HOME%\toolchains\llvm\prebuilt\windows-x86_64\bin
+set CXX="%NDK_BIN%\clang++.exe" --target=%TRIPLE% -fPIC -std=c++17 %DBG_CXX%
+set AR="%NDK_BIN%\llvm-ar.exe"
+set TSC=%TSLANG% -mtriple=%TRIPLE% -relocation-model=pic %DBG% -mm=%MM% --emit=obj --export=none --nowarn --no-default-lib
+
+set OUT=%ROOT%\__build\android\%ABI%\defaultlib
+set OBJ=%ROOT%\__build\android\%ABI%\obj-%MODE%-%MM%
+set LIB_OUT=%OUT%\lib\%MODE%\%MM%
+set DLL_OUT=%OUT%\dll\%MODE%\%MM%
+
+echo === %ABI% %MODE% %MM%
+if exist "%OBJ%" rd /s /q "%OBJ%"
+if exist "%LIB_OUT%" rd /s /q "%LIB_OUT%"
+if exist "%DLL_OUT%" rd /s /q "%DLL_OUT%"
+md "%OBJ%" "%LIB_OUT%" "%DLL_OUT%"
+
+for %%w in (io datetime regex thread http_stub) do (
+    %CXX% -c "%ROOT%\src\wrappers\%%w.cpp" -o "%OBJ%\%%w.o" || exit /b 1
+)
+
+%TSC% "%ROOT%\src\lib.linux.ts" -o "%OBJ%\lib.linux.o" || exit /b 1
+%TSC% "%ROOT%\src\lib.ts" -o "%OBJ%\lib.o" || exit /b 1
+
+set OBJS="%OBJ%\lib.o" "%OBJ%\lib.linux.o" "%OBJ%\io.o" "%OBJ%\datetime.o" "%OBJ%\regex.o" "%OBJ%\thread.o" "%OBJ%\http_stub.o"
+%AR% rcs "%LIB_OUT%\libTypeScriptDefaultLib.a" %OBJS% || exit /b 1
+%CXX% -shared %OBJS% -lm -o "%DLL_OUT%\libTypeScriptDefaultLib.so" || exit /b 1
+
+rd /s /q "%OBJ%"
+
+rem the declarations a program compiled against this tree reads, and which compiler built it
+xcopy /E /I /Y /Q "%ROOT%\src" "%OUT%" > nul || exit /b 1
+%TSLANG% --version > "%OUT%\COMPILER_VERSION.txt" 2>&1
+exit /b 0
diff --git a/src/wrappers/http_stub.cpp b/src/wrappers/http_stub.cpp
@@ -0,0 +1,55 @@
+#include <cstddef>
+
+#include "tslang_export.h"
+
+// The http_* functions lib.ts calls (see http_linux.cpp), for a target with no HTTP client
+// (Android, where libcurl is not part of the platform). Every request fails, as one does in
+// http_linux.cpp when curl cannot start, so fetch() throws instead of the library failing to
+// link.
+struct HttpResponse
+{
+    int errorCode = -1;
+};
+
+extern "C" TSLANG_EXPORT HttpResponse *http_request(const char *, const char *, const char *, const char *, size_t)
+{
+    return new HttpResponse();
+}
+
+extern "C" TSLANG_EXPORT bool http_response_success(HttpResponse *)
+{
+    return false;
+}
+
+extern "C" TSLANG_EXPORT int http_response_error_code(HttpResponse *r)
+{
+    return r->errorCode;
+}
+
+extern "C" TSLANG_EXPORT int http_response_status(HttpResponse *)
+{
+    return 0;
+}
+
+extern "C" TSLANG_EXPORT size_t http_response_headers_length(HttpResponse *)
+{
+    return 0;
+}
+
+extern "C" TSLANG_EXPORT void http_response_headers_copy_to(HttpResponse *, char *, size_t)
+{
+}
+
+extern "C" TSLANG_EXPORT size_t http_response_body_length(HttpResponse *)
+{
+    return 0;
+}
+
+extern "C" TSLANG_EXPORT void http_response_body_copy_to(HttpResponse *, char *, size_t)
+{
+}
+
+extern "C" TSLANG_EXPORT void http_response_free(HttpResponse *r)
+{
+    delete r;
+}