author David Ludwig
Sat, 29 Nov 2014 10:09:30 -0500
changeset 9247 eddb899239fe
parent 9242 f4d353bd5d16
child 9255 c2ef0d8d6da0
permissions -rw-r--r--
WinRT: bug and data-integrity fixes for SDL_GetPrefPath()

This change does a few things, all with regards to the WinRT implementation of

1. it fixes a bug whereby SDL_GetPrefPath() did not create the directory it
returned. On other SDL platforms, SDL_GetPrefPath() will create separate
directories for its 'org' and 'app' folders. Without this, attempts to create
files in the pref-path would fail, unless those directories were first created
by the app, or by some other library the app used. This change makes sure
that these directories get created, before SDL_GetPrefPath() returns to its

2. it defaults to having SDL_GetPrefPath() return a WinRT 'Local' folder
on all platforms. Previously, for Windows Store apps, it would have used a
different, 'Roaming' folder. Files in Roaming folders can be automatically,
and synchronized across multiple devices by Windows. This synchronization can
happen while the app runs, with new files being copied into a running app's
pref-path. Unless an app is specifically designed to handle this scenario,
there is a chance that save-data could be overwritten in unwanted or
unexpected ways.

The default is now to use a Local folder, which does not get synchronized, and
which is arguably a bit safer to use. Apps that wish to use Roaming folders
can do so by setting SDL_HINT_WINRT_PREF_PATH_ROOT to "roaming", however it
is recommended that one first read Microsoft's documentation for Roaming
files, a link to which is provided in

To preserve older pref-path selection behavior (found in SDL 2.0.3, as well as
many pre-2.0.4 versions of SDL from, which uses a Roaming path
in Windows Store apps, and a Local path in Windows Phone, set

Please note that Roaming paths are not supported on Windows Phone 8.0, due to
limitations in the OS itself. Attempts to use this will fail.
(Windows Phone 8.1 does not have this limitation, however.)

3. It makes SDL_GetPrefPath(), when on Windows Phone 8.0, and when
SDL_HINT_WINRT_PREF_PATH_ROOT is set to "roaming", return NULL, rather than
silently defaulting to a Local path (then switching to a Roaming path if and
when the user upgraded to Windows Phone 8.1).
     1 WinRT
     2 =====
     4 This port allows SDL applications to run on Microsoft's platforms that require
     5 use of "Windows Runtime", aka. "WinRT", APIs.  WinRT apps are currently
     6 full-screen only, and run in what Microsoft sometimes refers to as their
     7 "Modern" (formerly, "Metro"), environment.  For Windows 8.x, Microsoft may also
     8 refer to them as "Windows Store" apps, due to them being distributed,
     9 primarily, via a Microsoft-run online store (of the same name).
    11 Some of the operating systems that include WinRT, are:
    13 * Windows 8.x
    14 * Windows RT 8.x (aka. Windows 8.x for ARM processors)
    15 * Windows Phone 8.x
    18 Requirements
    19 ------------
    21 * Microsoft Visual C++ (aka Visual Studio), either 2013 or 2012 versions
    22   - Free, "Community" or "Express" editions may be used, so long as they
    23     include  support for either "Windows Store" or "Windows Phone" apps.
    24     "Express" versions marked as supporting "Windows Desktop" development
    25     typically do not include support for creating WinRT apps, to note.
    26     (The "Community" edition of Visual C++ 2013 does, however, support both
    27     desktop/Win32 and WinRT development).
    28   - Visual C++ 2012 can only build apps that target versions 8.0 of Windows,
    29     or  Windows Phone.  8.0-targetted apps will run on devices running 8.1
    30     editions of Windows, however they will not be able to take advantage of
    31     8.1-specific features.
    32   - Visual C++ 2013 cannot create app projects that target Windows 8.0.
    33     Visual C++ 2013 Update 4, can create app projects for Windows Phone 8.0,
    34     Windows Phone 8.1, and Windows 8.1, but not Windows 8.0.  An optional
    35     Visual Studio add-in, "Tools for Maintaining Store apps for Windows 8",
    36     allows Visual C++ 2013 to load and build Windows 8.0 projects that were
    37     created with Visual C++ 2012, so long as Visual C++ 2012 is installed
    38     on the same machine.  More details on targeting different versions of
    39     Windows can found at the following web pages:
    40       - [Develop apps by using Visual Studio 2013](
    41       - [To add the Tools for Maintaining Store apps for Windows 8](
    42 * A valid Microsoft account - This requirement is not imposed by SDL, but
    43   rather by Microsoft's Visual C++ toolchain.  This is required to launch or 
    44   debug apps.
    47 Status
    48 ------
    50 Here is a rough list of what works, and what doens't:
    52 * What works:
    53   * compilation via Visual C++ 2012 and 2013
    54   * compile-time platform detection for SDL programs.  The C/C++ #define,
    55     `__WINRT__`, will be set to 1 (by SDL) when compiling for WinRT.
    56   * GPU-accelerated 2D rendering, via SDL_Renderer.
    57   * software rendering, via either SDL_Surface (optionally in conjunction with
    58     SDL_GetWindowSurface() and SDL_UpdateWindowSurface()) or via the
    59     SDL_Renderer APIs
    60   * threads.  Significant chunks of Win32's threading APIs are not available in
    61     WinRT.  A new, SDL threading backend was built using C++11's threading APIs
    62     (std::thread, std::mutex, std::condition_variable, etc.), which C or C++
    63     programs alike can access via SDL's threading APIs.  Support for thread
    64     priorities is not, however, currently available, due to restrictions in
    65     WinRT's own API set.
    66   * timers (via SDL_GetTicks(), SDL_AddTimer(), SDL_GetPerformanceCounter(),
    67     SDL_GetPerformanceFrequency(), etc.)
    68   * file I/O via SDL_RWops
    69   * mouse input  (unsupported on Windows Phone)
    70   * audio, via a modified version of SDL's XAudio2 backend
    71   * .DLL file loading.  Libraries must be packaged inside applications.  Loading
    72     anything outside of the app is not supported.
    73   * system path retrieval via SDL's filesystem APIs
    74   * game controllers.  Support is provided via the SDL_Joystick and
    75     SDL_GameController APIs, and is backed by Microsoft's XInput API.
    76   * multi-touch input
    77   * app events.  SDL_APP_WILLENTER* and SDL_APP_DIDENTER* events get sent out as
    78     appropriate.
    80     sent out on app suspend and resume, respectively.  SDL_WINDOWEVENT_SHOWN and
    81     SDL_WINDOWEVENT_HIDDEN are also sent, but not necessarily on app suspend or
    82     resume, as WinRT treats these two concepts differently..
    83   * using Direct3D 11.x APIs outside of SDL.  Non-XAML / Direct3D-only apps can
    84     choose to render content directly via Direct3D, using SDL to manage the
    85     internal WinRT window, as well as input and audio.  (Use
    86     SDL_GetWindowWMInfo() to get the WinRT 'CoreWindow', and pass it into
    87     IDXGIFactory2::CreateSwapChainForCoreWindow() as appropriate.)
    89 * What partially works:
    90   * keyboard input.  Most of WinRT's documented virtual keys are supported, as
    91     well as many keys with documented hardware scancodes.
    92   * OpenGL.  Experimental support for OpenGL ES 2 is available via the ANGLE
    93     project, using either MS Open Technologies' repository, at 
    94 (both the "winrt" and "future-dev"
    95     branches are supported), or the official ANGLE repository, at
    97   * SDLmain.  WinRT uses a different signature for each app's main() function.
    98     SDL-based apps that use this port must compile in SDL_winrt_main_NonXAML.cpp
    99     (in `SDL\src\main\winrt\`) directly in order for their C-style main()
   100     functions to be called.
   101   * XAML interoperability.  This feature is currently experimental (there are
   102     **many** known bugs in this, at present!), preliminary, and only for
   103     Windows 8.x/RT at the moment.  Windows Phone + XAML support is still
   104     pending.
   106 * What doesn't work:
   107   * compilation with anything other than Visual C++ 2012 or 2013
   108   * programmatically-created custom cursors.  These don't appear to be supported
   109     by WinRT.  Different OS-provided cursors can, however, be created via
   110     SDL_CreateSystemCursor() (unsupported on Windows Phone)
   111   * SDL_WarpMouseInWindow() or SDL_WarpMouseGlobal().  This are not currently
   112     supported by WinRT itself.
   113   * joysticks and game controllers that aren't supported by Microsoft's XInput
   114     API.
   115   * probably anything else that's not listed as supported
   119 Caveats
   120 -------
   122 #### SDL_GetPrefPath() usage when upgrading existing WinRT apps to SDL 2.0.4
   124 SDL 2.0.4 fixes two bugs found in SDL_GetPrefPath() which can affect
   125 an app's save data.  These bugs only apply to WinRT apps (and not
   126 Windows Desktop / Win32 apps, or to apps on any other SDL platform).
   127 In particular, for older versions of SDL (anything before 2.0.4):
   129 1. SDL_GetPrefPath() would return an invalid path, one in which attempts
   130    to write files to would fail, in many cases.  Some of the path elements
   131    returned by SDL_GetPrefPath() would not get created (as done on other
   132    SDL platforms).  Files could be written to this path, however apps would
   133    need to explicitly create the missing directories first.
   135 2. SDL_GetPrefPath() would return a path inside a WinRT 'Roaming' folder,
   136    the contents of which could get automatically synchronized across multiple
   137    devices, by Windows.  This process could occur while an app was running.
   138    Apps which were not explicitly built to handle this scenario could
   139    have their SDL_GetPrefPath-backed save data swapped out by Windows at
   140    unexpected times, which raised potential for data-loss (if apps weren't
   141    designed to support live file-synchronization.)
   144 SDL_GetPrefPath(), starting with SDL 2.0.4, addresses these by:
   146 1. making sure that SDL_GetPrefPath() returns a directory in which data
   147    can be written to immediately, without first needing to create directories.
   149 2. basing SDL_GetPrefPath() off of a non-Roaming / 'Local' folder, the
   150    contents of which do not get automatically synchronized across devices,
   151    and which may be safer in terms of data-integrity.
   153    Apps can, at their discretion, choose to utilize WinRT's Roaming
   154    functionality by calling the following before calling SDL_GetPrefPath():
   156        SDL_SetHint(SDL_HINT_WINRT_PREF_PATH_ROOT, "roaming");
   158    Alternatively, to restore SDL_GetPrefPath()'s old behavior (found in
   159    SDL 2.0.3, and in many pre-2.0.4 versions of SDL found on,
   160    whereby a Roaming path is returned for Windows Store apps, and a Local
   161    folder is returned for Windows Phone apps, use the following code:
   163        SDL_SetHint(SDL_HINT_WINRT_PREF_PATH_ROOT, "old");
   165    Before using Roaming data in any capacity, it is highly recommended that
   166    one read the following:
   168    1. Microsoft's documentation on the Roaming data.  Details on this can be
   169       found on MSDN, at:
   170       [Guidelines for roaming app data](
   172    2. the SDL documentation for SDL_HINT_WINRT_PREF_PATH_ROOT, which is
   173       listed inside SDL_hints.h.
   175    Please note that Roaming support is not available on Windows Phone 8.0,
   176    due to limitations in the OS itself.  Attempts to use it will fail, with
   177    SDL_GetPrefPath() returning NULL (if SDL_HINT_WINRT_PREF_PATH_ROOT is
   178    set to "roaming" on that platform).  Windows Phone 8.1 does not have this
   179    limitation, and does support Roaming data.
   183 Setup, High-Level Steps
   184 -----------------------
   186 The steps for setting up a project for an SDL/WinRT app looks like the
   187 following, at a high-level:
   189 1. create a new Visual C++ project using Microsoft's template for a,
   190    "Direct3D App".
   191 2. remove most of the files from the project.
   192 3. make your app's project directly reference SDL/WinRT's own Visual C++
   193    project file, via use of Visual C++'s "References" dialog.  This will setup
   194    the linker, and will copy SDL's .dll files to your app's final output.
   195 4. adjust your app's build settings, at minimum, telling it where to find SDL's
   196    header files.
   197 5. add a file that contains a WinRT-appropriate main function.
   198 6. add SDL-specific app code.
   199 7. build and run your app.
   202 Setup, Detailed Steps
   203 ---------------------
   205 ### 1. Create a new project ###
   207 Create a new project using one of Visual C++'s templates for a plain, non-XAML,
   208 "Direct3D App" (XAML support for SDL/WinRT is not yet ready for use).  If you
   209 don't see one of these templates, in Visual C++'s 'New Project' dialog, try
   210 using the textbox titled, 'Search Installed Templates' to look for one.
   213 ### 2. Remove unneeded files from the project ###
   215 In the new project, delete any file that has one of the following extensions:
   217 - .cpp
   218 - .h
   219 - .hlsl
   221 When you are done, you should be left with a few files, each of which will be a
   222 necessary part of your app's project.  These files will consist of:
   224 - an .appxmanifest file, which contains metadata on your WinRT app.  This is
   225   similar to an Info.plist file on iOS, or an AndroidManifest.xml on Android.
   226 - a few .png files, one of which is a splash screen (displayed when your app
   227   launches), others are app icons.
   228 - a .pfx file, used for code signing purposes.
   231 ### 3. Add references to SDL's project files ###
   233 SDL/WinRT can be built in multiple variations, spanning across three different
   234 CPU architectures (x86, x64, and ARM) and two different configurations
   235 (Debug and Release).  WinRT and Visual C++ do not currently provide a means
   236 for combining multiple variations of one library into a single file.
   237 Furthermore, it does not provide an easy means for copying pre-built .dll files
   238 into your app's final output (via Post-Build steps, for example).  It does,
   239 however, provide a system whereby an app can reference the MSVC projects of
   240 libraries such that, when the app is built:
   242 1. each library gets built for the appropriate CPU architecture(s) and WinRT
   243    platform(s).
   244 2. each library's output, such as .dll files, get copied to the app's build 
   245    output.
   247 To set this up for SDL/WinRT, you'll need to run through the following steps:
   249 1. open up the Solution Explorer inside Visual C++ (under the "View" menu, then
   250    "Solution Explorer")
   251 2. right click on your app's solution.
   252 3. navigate to "Add", then to "Existing Project..."
   253 4. find SDL/WinRT's Visual C++ project file and open it.  Different project
   254    files exist for different WinRT platforms.  All of them are in SDL's
   255    source distribution, in the following directories:
   256     * `VisualC-WinRT/WinPhone80_VS2012/` - for Windows Phone 8.0 apps
   257     * `VisualC-WinRT/WinPhone81_VS2013/` - for Windows Phone 8.1 apps
   258     * `VisualC-WinRT/WinRT80_VS2012/` - for Windows 8.0 apps
   259     * `VisualC-WinRT/WinRT81_VS2013/` - for Windows 8.1 apps
   260 5. once the project has been added, right-click on your app's project and
   261    select, "References..."
   262 6. click on the button titled, "Add New Reference..."
   263 7. check the box next to SDL
   264 8. click OK to close the dialog
   265 9. SDL will now show up in the list of references.  Click OK to close that
   266    dialog.
   268 Your project is now linked to SDL's project, insofar that when the app is
   269 built, SDL will be built as well, with its build output getting included with
   270 your app.
   273 ### 4. Adjust Your App's Build Settings ###
   275 Some build settings need to be changed in your app's project.  This guide will
   276 outline the following:
   278 - making sure that the compiler knows where to find SDL's header files
   279 - **Optional for C++, but NECESSARY for compiling C code:** telling the
   280   compiler not to use Microsoft's C++ extensions for WinRT development.
   281 - **Optional:** telling the compiler not generate errors due to missing
   282   precompiled header files.
   284 To change these settings:
   286 1. right-click on the project
   287 2. choose "Properties"
   288 3. in the drop-down box next to "Configuration", choose, "All Configurations"
   289 4. in the drop-down box next to "Platform", choose, "All Platforms"
   290 5. in the left-hand list, expand the "C/C++" section
   291 6. select "General"
   292 7. edit the "Additional Include Directories" setting, and add a path to SDL's
   293    "include" directory
   294 8. **Optional: to enable compilation of C code:** change the setting for
   295    "Consume Windows Runtime Extension" from "Yes (/ZW)" to "No".  If you're 
   296    working with a completely C++ based project, this step can usually be 
   297    omitted.
   298 9. **Optional: to disable precompiled headers (which can produce 
   299    'stdafx.h'-related build errors, if setup incorrectly:** in the left-hand 
   300    list, select "Precompiled Headers", then change the setting for "Precompiled 
   301    Header" from "Use (/Yu)" to "Not Using Precompiled Headers".
   302 10. close the dialog, saving settings, by clicking the "OK" button
   305 ### 5. Add a WinRT-appropriate main function to the app. ###
   307 C/C++-based WinRT apps do contain a `main` function that the OS will invoke when 
   308 the app starts launching. The parameters of WinRT main functions are different 
   309 than those found on other platforms, Win32 included.  SDL/WinRT provides a 
   310 platform-appropriate main function that will perform these actions, setup key 
   311 portions of the app, then invoke a classic, C/C++-style main function (that take 
   312 in "argc" and "argv" parameters).  The code for this file is contained inside 
   313 SDL's source distribution, under `src/main/winrt/SDL_winrt_main_NonXAML.cpp`.  
   314 You'll need to add this file, or a copy of it, to your app's project, and make 
   315 sure it gets compiled using a Microsoft-specific set of C++ extensions called 
   316 C++/CX.
   318 **NOTE: C++/CX compilation is currently required in at least one file of your 
   319 app's project.  This is to make sure that Visual C++'s linker builds a 'Windows 
   320 Metadata' file (.winmd) for your app.  Not doing so can lead to build errors.**
   322 To include `SDL_winrt_main_NonXAML.cpp`:
   324 1. right-click on your project (again, in Visual C++'s Solution Explorer), 
   325    navigate to "Add", then choose "Existing Item...".
   326 2. open `SDL_winrt_main_NonXAML.cpp`, which is found inside SDL's source 
   327    distribution, under `src/main/winrt/`.  Make sure that the open-file dialog 
   328    closes, either by double-clicking on the file, or single-clicking on it and 
   329    then clicking Add.
   330 3. right-click on the file (as listed in your project), then click on 
   331    "Properties...".
   332 4. in the drop-down box next to "Configuration", choose, "All Configurations"
   333 5. in the drop-down box next to "Platform", choose, "All Platforms"
   334 6. in the left-hand list, click on "C/C++"
   335 7. change the setting for "Consume Windows Runtime Extension" to "Yes (/ZW)".
   336 8. click the OK button.  This will close the dialog.
   339 ### 6. Add app code and assets ###
   341 At this point, you can add in SDL-specific source code.  Be sure to include a 
   342 C-style main function (ie: `int main(int argc, char *argv[])`).  From there you 
   343 should be able to create a single `SDL_Window` (WinRT apps can only have one 
   344 window, at present), as well as an `SDL_Renderer`.  Direct3D will be used to 
   345 draw content.  Events are received via SDL's usual event functions 
   346 (`SDL_PollEvent`, etc.)  If you have a set of existing source files and assets, 
   347 you can start adding them to the project now.  If not, or if you would like to 
   348 make sure that you're setup correctly, some short and simple sample code is 
   349 provided below.
   352 #### 6.A. ... when creating a new app ####
   354 If you are creating a new app (rather than porting an existing SDL-based app), 
   355 or if you would just like a simple app to test SDL/WinRT with before trying to 
   356 get existing code working, some working SDL/WinRT code is provided below.  To 
   357 set this up:
   359 1. right click on your app's project
   360 2. select Add, then New Item.  An "Add New Item" dialog will show up.
   361 3. from the left-hand list, choose "Visual C++"
   362 4. from the middle/main list, choose "C++ File (.cpp)"
   363 5. near the bottom of the dialog, next to "Name:", type in a name for your 
   364 source file, such as, "main.cpp".
   365 6. click on the Add button.  This will close the dialog, add the new file to 
   366 your project, and open the file in Visual C++'s text editor.
   367 7. Copy and paste the following code into the new file, then save it.
   370     #include <SDL.h>
   372     int main(int argc, char **argv)
   373     {
   374         SDL_DisplayMode mode;
   375         SDL_Window * window = NULL;
   376         SDL_Renderer * renderer = NULL;
   377         SDL_Event evt;
   379         if (SDL_Init(SDL_INIT_VIDEO) != 0) {
   380             return 1;
   381         }
   383         if (SDL_GetCurrentDisplayMode(0, &mode) != 0) {
   384             return 1;
   385         }
   387         if (SDL_CreateWindowAndRenderer(mode.w, mode.h, SDL_WINDOW_FULLSCREEN, &window, &renderer) != 0) {
   388             return 1;
   389         }
   391         while (1) {
   392             while (SDL_PollEvent(&evt)) {
   393             }
   395             SDL_SetRenderDrawColor(renderer, 0, 255, 0, 255);
   396             SDL_RenderClear(renderer);
   397             SDL_RenderPresent(renderer);
   398         }
   399     }
   402 #### 6.B. Adding code and assets ####
   404 If you have existing code and assets that you'd like to add, you should be able 
   405 to add them now.  The process for adding a set of files is as such.
   407 1. right click on the app's project
   408 2. select Add, then click on "New Item..."
   409 3. open any source, header, or asset files as appropriate.  Support for C and 
   410 C++ is available.
   412 Do note that WinRT only supports a subset of the APIs that are available to 
   413 Win32-based apps.  Many portions of the Win32 API and the C runtime are not 
   414 available.
   416 A list of unsupported C APIs can be found at 
   417 <>
   419 General information on using the C runtime in WinRT can be found at 
   420 <>
   422 A list of supported Win32 APIs for Windows 8/RT apps can be found at 
   423 <>.  To note, 
   424 the list of supported Win32 APIs for Windows Phone 8 development is different.  
   425 That list can be found at 
   426 <>
   429 ### 7. Build and run your app ###
   431 Your app project should now be setup, and you should be ready to build your app.  
   432 To run it on the local machine, open the Debug menu and choose "Start 
   433 Debugging".  This will build your app, then run your app full-screen.  To switch 
   434 out of your app, press the Windows key.  Alternatively, you can choose to run 
   435 your app in a window.  To do this, before building and running your app, find 
   436 the drop-down menu in Visual C++'s toolbar that says, "Local Machine".  Expand 
   437 this by clicking on the arrow on the right side of the list, then click on 
   438 Simulator.  Once you do that, any time you build and run the app, the app will 
   439 launch in window, rather than full-screen.
   442 #### 7.A. Running apps on ARM-based devices ####
   444 To build and run the app on ARM-based, "Windows RT" devices, you'll need to:
   446 - install Microsoft's "Remote Debugger" on the device.  Visual C++ installs and 
   447   debugs ARM-based apps via IP networks.
   448 - change a few options on the development machine, both to make sure it builds 
   449   for ARM (rather than x86 or x64), and to make sure it knows how to find the 
   450   Windows RT device (on the network).
   452 Microsoft's Remote Debugger can be found at 
   453 <>.  Please note 
   454 that separate versions of this debugger exist for different versions of Visual 
   455 C++, one for debugging with MSVC 2012, another for debugging with MSVC 2013.
   457 To setup Visual C++ to launch your app on an ARM device:
   459 1. make sure the Remote Debugger is running on your ARM device, and that it's on 
   460    the same IP network as your development machine.
   461 2. from Visual C++'s toolbar, find a drop-down menu that says, "Win32".  Click 
   462    it, then change the value to "ARM".
   463 3. make sure Visual C++ knows the hostname or IP address of the ARM device.  To 
   464    do this:
   465     1. open the app project's properties
   466     2. select "Debugging"
   467     3. next to "Machine Name", enter the hostname or IP address of the ARM 
   468        device
   469     4. if, and only if, you've turned off authentication in the Remote Debugger,
   470        then change the setting for "Require Authentication" to No
   471     5. click "OK"
   472 4. build and run the app (from Visual C++).  The first time you do this, a 
   473    prompt will show up on the ARM device, asking for a Microsoft Account.  You 
   474    do, unfortunately, need to log in here, and will need to follow the 
   475    subsequent registration steps in order to launch the app.  After you do so, 
   476    if the app didn't already launch, try relaunching it again from within Visual 
   477    C++.
   480 Troubleshooting
   481 ---------------
   483 #### Build fails with message, "error LNK2038: mismatch detected for 'vccorlib_lib_should_be_specified_before_msvcrt_lib_to_linker'"
   485 Try adding the following to your linker flags.  In MSVC, this can be done by
   486 right-clicking on the app project, navigating to Configuration Properties ->
   487 Linker -> Command Line, then adding them to the Additional Options
   488 section.
   490 * For Release builds / MSVC-Configurations, add:
   492     /nodefaultlib:vccorlib /nodefaultlib:msvcrt vccorlib.lib msvcrt.lib
   494 * For Debug builds / MSVC-Configurations, add:
   496     /nodefaultlib:vccorlibd /nodefaultlib:msvcrtd vccorlibd.lib msvcrtd.lib