Keep the MSVC aliases out of the installed headers

htsglobal.h is installed and reached from httrack-library.h, so defining fseeko,
ftello and timegm there rewrote those identifiers in every consumer's own code on
MSVC: a caller's struct member, C++ method or compat declaration named timegm
silently became _mkgmtime. Move the block to htslib.h, which is not installed and
already holds the strcasecmp/snprintf aliases; both call sites reach it through
htscore.h.

Drop the (off_t) cast on the truncate as well. It is 32-bit on MSVC, so the same
resume past 2GB it would have wrapped on the seek it also wraps here, and
_chsize_s then destroys the partial file before the seek is reached.

Restore NDEBUG/_DEBUG, which the legacy .vcproj set and the port had dropped,
leaving assert() live in the release DLL.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Signed-off-by: Xavier Roche <roche@httrack.com>

.github/workflows/windows-build.yml

@@ -0,0 +1,73 @@
+# Windows build of libhttrack (VS2022 v143 + vcpkg).
+#
+# The autotools CI covers the unix builds; this covers the MSVC one, which had
+# no coverage at all and had drifted (the old .vcproj pinned OpenSSL 1.0.1j).
+# libhttrack.dll is what the WinHTTrack GUI links against.
+name: windows-build
+
+on:
+  push:
+    branches: [master]
+  pull_request:
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+jobs:
+  libhttrack:
+    runs-on: windows-2022
+    strategy:
+      fail-fast: false
+      matrix:
+        platform: [x64, Win32]
+        configuration: [Release]
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          submodules: recursive   # coucal lives in src/coucal
+
+      # Located through vswhere rather than microsoft/setup-msbuild: the repo
+      # only allows GitHub-owned actions.
+      - name: Find MSBuild
+        shell: pwsh
+        run: |
+          $vswhere = "${env:ProgramFiles(x86)}\Microsoft Visual Studio\Installer\vswhere.exe"
+          $msbuild = & $vswhere -latest -products * -requires Microsoft.Component.MSBuild `
+            -find MSBuild\**\Bin\MSBuild.exe | Select-Object -First 1
+          if (-not $msbuild) { throw "MSBuild not found" }
+          Write-Host "MSBuild: $msbuild"
+          "MSBUILD=$msbuild" | Out-File -FilePath $env:GITHUB_ENV -Append
+
+      - name: Enable vcpkg MSBuild integration
+        shell: pwsh
+        run: vcpkg integrate install
+
+      - name: Build libhttrack
+        shell: pwsh
+        run: |
+          & $env:MSBUILD src\libhttrack.vcxproj `
+            /m `
+            /p:Configuration=${{ matrix.configuration }} `
+            /p:Platform=${{ matrix.platform }} `
+            /p:VcpkgEnableManifest=true `
+            /flp:LogFile=msbuild.log`;Verbosity=normal
+
+      # WinHTTrack links src\$(Platform)\$(Configuration)\libhttrack.lib, so the
+      # import lib and the DLL both have to land there under that exact name.
+      - name: Check the DLL and import lib landed where WinHTTrack expects
+        shell: pwsh
+        run: |
+          $dir = "src\${{ matrix.platform }}\${{ matrix.configuration }}"
+          foreach ($f in @("libhttrack.dll", "libhttrack.lib")) {
+            if (-not (Test-Path "$dir\$f")) { throw "missing $dir\$f" }
+            Write-Host "found $dir\$f"
+          }
+
+      - name: Upload MSBuild log
+        if: always()
+        uses: actions/upload-artifact@v4
+        with:
+          name: msbuild-${{ matrix.platform }}-${{ matrix.configuration }}
+          path: msbuild.log
+          if-no-files-found: ignore

src/htsback.c

@@ -3868,8 +3868,9 @@ void back_wait(struct_back * sback, httrackp * opt, cache_back * cache,
                               // drop bytes past the resume point; a silent
                               // failure could leave a stale tail, so on error
                               // drop the partial and refetch the whole file
-                              if (HTS_FTRUNCATE(back[i].r.out,
-                                                (off_t) resume) != 0) {
+                              /* not (off_t): 32-bit on MSVC, wrapping a resume
+                                 past 2GB */
+                              if (HTS_FTRUNCATE(back[i].r.out, resume) != 0) {
                                 fclose(back[i].r.out);
                                 back[i].r.out = NULL;
                                 url_savename_refname_remove(
@@ -3881,7 +3882,9 @@ void back_wait(struct_back * sback, httrackp * opt, cache_back * cache,
                                            "Can not truncate partial file, "
                                            "restarting");
                               } else {
-                                fseeko(back[i].r.out, (off_t) resume, SEEK_SET);
+                                /* not (off_t): 32-bit on MSVC, truncating a
+                                   resume past 2GB */
+                                fseeko(back[i].r.out, resume, SEEK_SET);
                                 /* create a temporary reference file in case of
                                  * broken mirror */
                                 if (back_serialize_ref(opt, &back[i]) != 0) {

src/htsdns_selftest.c

@@ -133,9 +133,10 @@ static struct addrinfo *mock_mkai(const mock_addr *a) {
   return ai;
 }
 
-static int mock_getaddrinfo(const char *node, const char *service,
-                            const struct addrinfo *hints,
-                            struct addrinfo **res) {
+static int HTS_RESOLVER_CALL mock_getaddrinfo(const char *node,
+                                              const char *service,
+                                              const struct addrinfo *hints,
+                                              struct addrinfo **res) {
   mock_host *const h = mock_find(node);
   const int want = (hints != NULL) ? hints->ai_family : PF_UNSPEC;
   struct addrinfo *head = NULL, *tail = NULL;
@@ -164,7 +165,7 @@ static int mock_getaddrinfo(const char *node, const char *service,
   return 0;
 }
 
-static void mock_freeaddrinfo(struct addrinfo *res) {
+static void HTS_RESOLVER_CALL mock_freeaddrinfo(struct addrinfo *res) {
   while (res != NULL) {
     struct addrinfo *const next = res->ai_next;
 

src/htslib.c

@@ -5018,7 +5018,7 @@ static struct addrinfo *resolver_make_ai(const char *ip, int want_family) {
   return ai;
 }
 
-static void override_freeaddrinfo(struct addrinfo *res) {
+static void HTS_RESOLVER_CALL override_freeaddrinfo(struct addrinfo *res) {
   while (res != NULL) {
     struct addrinfo *const next = res->ai_next;
 
@@ -5028,9 +5028,10 @@ static void override_freeaddrinfo(struct addrinfo *res) {
   }
 }
 
-static int override_getaddrinfo(const char *node, const char *service,
-                                const struct addrinfo *hints,
-                                struct addrinfo **res) {
+static int HTS_RESOLVER_CALL override_getaddrinfo(const char *node,
+                                                  const char *service,
+                                                  const struct addrinfo *hints,
+                                                  struct addrinfo **res) {
   const char *const spec = getenv("HTTRACK_DEBUG_RESOLVE");
   const int want = (hints != NULL) ? hints->ai_family : PF_UNSPEC;
   const char *colon;

src/htslib.h

@@ -493,6 +493,14 @@ HTS_STATIC int strcmpnocase(const char *a, const char *b) {
 #define snprintf _snprintf
 #endif
 
+/* MSVC ships these POSIX functions under other names. Kept out of the installed
+   headers: they would rewrite the same identifiers in a consumer's own code. */
+#ifdef _MSC_VER
+#define fseeko _fseeki64
+#define ftello _ftelli64
+#define timegm _mkgmtime
+#endif
+
 #define strfield2(f,s) ( (strlen(f)!=strlen(s)) ? 0 : (strfield(f,s)) )
 
 // is this MIME an hypertext MIME (text/html), html/js-style or other script/text type?

src/htsnet.h

@@ -309,10 +309,19 @@ typedef socklen_t SOClen;
     self-test can script DNS answers (families, multiplicity, errors)
     in-process. The free function must match its getaddrinfo (a fake allocates
     its own chain), hence the pair. */
+/* Winsock's resolver is __stdcall; a plain pointer only compiles on x64, where
+   there is one convention. Backend implementations must carry this too. */
+#ifdef _WIN32
+#define HTS_RESOLVER_CALL WSAAPI
+#else
+#define HTS_RESOLVER_CALL
+#endif
+
 typedef struct hts_resolver_backend {
-  int (*getaddrinfo)(const char *node, const char *service,
-                     const struct addrinfo *hints, struct addrinfo **res);
-  void (*freeaddrinfo)(struct addrinfo *res);
+  int(HTS_RESOLVER_CALL *getaddrinfo)(const char *node, const char *service,
+                                      const struct addrinfo *hints,
+                                      struct addrinfo **res);
+  void(HTS_RESOLVER_CALL *freeaddrinfo)(struct addrinfo *res);
 } hts_resolver_backend;
 
 /** Install a resolver backend for the process; NULL restores the libc default.

src/libhttrack.vcxproj

@@ -0,0 +1,143 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+
+  <ItemGroup Label="ProjectConfigurations">
+    <ProjectConfiguration Include="Debug|Win32">
+      <Configuration>Debug</Configuration>
+      <Platform>Win32</Platform>
+    </ProjectConfiguration>
+    <ProjectConfiguration Include="Release|Win32">
+      <Configuration>Release</Configuration>
+      <Platform>Win32</Platform>
+    </ProjectConfiguration>
+    <ProjectConfiguration Include="Debug|x64">
+      <Configuration>Debug</Configuration>
+      <Platform>x64</Platform>
+    </ProjectConfiguration>
+    <ProjectConfiguration Include="Release|x64">
+      <Configuration>Release</Configuration>
+      <Platform>x64</Platform>
+    </ProjectConfiguration>
+  </ItemGroup>
+
+  <PropertyGroup Label="Globals">
+    <VCProjectVersion>17.0</VCProjectVersion>
+    <ProjectGuid>{E76AD871-54C1-45E8-A657-6117ADEFFB46}</ProjectGuid>
+    <RootNamespace>libhttrack</RootNamespace>
+    <WindowsTargetPlatformVersion Condition="'$(WindowsTargetPlatformVersion)'==''">10.0</WindowsTargetPlatformVersion>
+  </PropertyGroup>
+
+  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.Default.props" />
+
+  <PropertyGroup Condition="'$(Configuration)'=='Debug'" Label="Configuration">
+    <ConfigurationType>DynamicLibrary</ConfigurationType>
+    <UseDebugLibraries>true</UseDebugLibraries>
+    <PlatformToolset>v143</PlatformToolset>
+    <CharacterSet>MultiByte</CharacterSet>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)'=='Release'" Label="Configuration">
+    <ConfigurationType>DynamicLibrary</ConfigurationType>
+    <UseDebugLibraries>false</UseDebugLibraries>
+    <PlatformToolset>v143</PlatformToolset>
+    <CharacterSet>MultiByte</CharacterSet>
+  </PropertyGroup>
+
+  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.props" />
+
+  <!-- OpenSSL 3.x and zlib come from vcpkg. Dynamic triplets: the DLLs ship with
+       the app, so an OpenSSL CVE is a DLL swap rather than a rebuild. -->
+  <PropertyGroup>
+    <VcpkgEnableManifest>true</VcpkgEnableManifest>
+    <VcpkgTriplet Condition="'$(Platform)'=='Win32'">x86-windows</VcpkgTriplet>
+    <VcpkgTriplet Condition="'$(Platform)'=='x64'">x64-windows</VcpkgTriplet>
+    <!-- WinHTTrack links ..\httrack\src\$(Platform)\$(Configuration)\libhttrack.lib -->
+    <OutDir>$(MSBuildThisFileDirectory)$(Platform)\$(Configuration)\</OutDir>
+    <IntDir>$(MSBuildThisFileDirectory)$(Platform)\$(Configuration)\obj\</IntDir>
+    <TargetName>libhttrack</TargetName>
+  </PropertyGroup>
+
+  <ItemDefinitionGroup>
+    <ClCompile>
+      <!-- LIBHTTRACK_EXPORTS turns HTSEXT_API into __declspec(dllexport); ZLIB_DLL
+           imports zlib from its DLL. Windows 7 floor, matching WinHTTrack. -->
+      <PreprocessorDefinitions>WIN32;_WINDOWS;_MBCS;_USRDLL;LIBHTTRACK_EXPORTS;ZLIB_DLL;WINVER=0x0601;_WIN32_WINNT=0x0601;_CRT_SECURE_NO_WARNINGS;_CRT_NONSTDC_NO_DEPRECATE;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <AdditionalIncludeDirectories>$(MSBuildThisFileDirectory);$(MSBuildThisFileDirectory)coucal;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
+      <WarningLevel>Level3</WarningLevel>
+      <MultiProcessorCompilation>true</MultiProcessorCompilation>
+      <CompileAs>CompileAsC</CompileAs>
+    </ClCompile>
+    <Link>
+      <!-- vcpkg auto-links libssl/libcrypto/zlib; only the OS import lib is explicit. -->
+      <AdditionalDependencies>Ws2_32.lib;%(AdditionalDependencies)</AdditionalDependencies>
+      <GenerateDebugInformation>true</GenerateDebugInformation>
+    </Link>
+  </ItemDefinitionGroup>
+
+  <ItemDefinitionGroup Condition="'$(Configuration)'=='Debug'">
+    <ClCompile>
+      <PreprocessorDefinitions>_DEBUG;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <Optimization>Disabled</Optimization>
+      <RuntimeLibrary>MultiThreadedDebugDLL</RuntimeLibrary>
+      <BasicRuntimeChecks>EnableFastChecks</BasicRuntimeChecks>
+      <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
+    </ClCompile>
+  </ItemDefinitionGroup>
+
+  <ItemDefinitionGroup Condition="'$(Configuration)'=='Release'">
+    <ClCompile>
+      <PreprocessorDefinitions>NDEBUG;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <Optimization>MaxSpeed</Optimization>
+      <RuntimeLibrary>MultiThreadedDLL</RuntimeLibrary>
+      <FunctionLevelLinking>true</FunctionLevelLinking>
+      <IntrinsicFunctions>true</IntrinsicFunctions>
+      <StringPooling>true</StringPooling>
+    </ClCompile>
+    <Link>
+      <EnableCOMDATFolding>true</EnableCOMDATFolding>
+      <OptimizeReferences>true</OptimizeReferences>
+    </Link>
+  </ItemDefinitionGroup>
+
+  <ItemGroup>
+    <ClCompile Include="coucal\coucal.c" />
+    <ClCompile Include="htsalias.c" />
+    <ClCompile Include="htsback.c" />
+    <ClCompile Include="htsbauth.c" />
+    <ClCompile Include="htscache.c" />
+    <ClCompile Include="htscache_selftest.c" />
+    <ClCompile Include="htscatchurl.c" />
+    <ClCompile Include="htscharset.c" />
+    <ClCompile Include="htsconcat.c" />
+    <ClCompile Include="htscore.c" />
+    <ClCompile Include="htscoremain.c" />
+    <ClCompile Include="htsdns_selftest.c" />
+    <ClCompile Include="htsencoding.c" />
+    <ClCompile Include="htsfilters.c" />
+    <ClCompile Include="htsftp.c" />
+    <ClCompile Include="htshash.c" />
+    <ClCompile Include="htshelp.c" />
+    <ClCompile Include="htsindex.c" />
+    <ClCompile Include="htslib.c" />
+    <ClCompile Include="htsmd5.c" />
+    <ClCompile Include="htsmodules.c" />
+    <ClCompile Include="htsname.c" />
+    <ClCompile Include="htsparse.c" />
+    <ClCompile Include="htsrobots.c" />
+    <ClCompile Include="htsselftest.c" />
+    <ClCompile Include="htssniff.c" />
+    <ClCompile Include="htsthread.c" />
+    <ClCompile Include="htstools.c" />
+    <ClCompile Include="htswizard.c" />
+    <ClCompile Include="htswrap.c" />
+    <ClCompile Include="htszlib.c" />
+    <ClCompile Include="md5.c" />
+    <ClCompile Include="minizip\ioapi.c" />
+    <ClCompile Include="minizip\iowin32.c" />
+    <ClCompile Include="minizip\mztools.c" />
+    <ClCompile Include="minizip\unzip.c" />
+    <ClCompile Include="minizip\zip.c" />
+    <ClCompile Include="punycode.c" />
+  </ItemGroup>
+
+  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />
+</Project>

src/vcpkg.json

@@ -0,0 +1,9 @@
+{
+  "$schema": "https://raw.githubusercontent.com/microsoft/vcpkg-tool/main/docs/vcpkg.schema.json",
+  "name": "libhttrack",
+  "version-string": "3.49",
+  "dependencies": [
+    "openssl",
+    "zlib"
+  ]
+}