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Bug 5382 - Issues building static library on Windows with CMake (missing stdlib functions)
Summary: Issues building static library on Windows with CMake (missing stdlib functions)
Status: RESOLVED FIXED
Alias: None
Product: SDL
Classification: Unclassified
Component: build (show other bugs)
Version: 2.0.12
Hardware: x86 Windows 10
: P2 major
Assignee: Sam Lantinga
QA Contact: Sam Lantinga
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2020-12-08 09:44 UTC by Philip Bennefall
Modified: 2020-12-08 20:19 UTC (History)
1 user (show)

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Description Philip Bennefall 2020-12-08 09:44:13 UTC 
When trying to build the latest version of SDL (version 2.0.12) with Visual Studio 2017 or 2019 via CMake, I get the following:

SDL_string.c
F:\build\SDL2\src\SDL2_project\src\stdlib\SDL_string.c(442): warning C4013: ‘wcslcpy’ undefined; assuming extern r
eturning int [F:\build\SDL2_build\SDL2-static.vcxproj] [F:\build\SDL2_project.vcxproj]
F:\build\SDL2\src\SDL2_project\src\stdlib\SDL_string.c(458): warning C4013: ‘wcslcat’ undefined; assuming extern r
eturning int [F:\build\SDL2_build\SDL2-static.vcxproj] [F:\build\SDL2_project.vcxproj]

And then I get linker errors. Version 2.0.10 builds just fine. I am building a 32 bit binary.

Digging a little deeper in SDL’s CMake script, I see on line 754:
if(LIBC)
if(WINDOWS AND NOT MINGW)
set(HAVE_LIBC TRUE)

And then a little further down in the same scope, there is a list of functions that are all assumed to be available in the C runtime. If I remove wcslcpy and wcslcat from this list, the build succeeds.

A patch for this as well as a few others for building SDL with CMake, are included in the VCPKG distribution from Microsoft. They are in the ports/SDL2 folder. 

https://github.com/Microsoft/vcpkg
Comment 1 Sam Lantinga 2020-12-08 17:21:28 UTC 
Fixed, thanks!
https://hg.libsdl.org/SDL/rev/0aa5690fb1c8

Also thank you for the heads up on the other patches in that folder. I accepted most of them for the next SDL release.
Comment 2 Ozkan Sezer 2020-12-08 17:39:24 UTC 
This one https://hg.libsdl.org/SDL/rev/be0a46c9b010 is wrong and also
problematic.

The _DLL macro usually is defined by MSVC dll projects, but it is not
defined by our MSVC project files because it has not been needed. The
autotools builds define DLL_EXPORT by way of libtool, but begin_code.h
doesn't check it. The result is: the autotools builds now export all
and every symbol it can find.

Solution would be defining DLL_EXPORT in CMake and MSVC project files
and changing _DLL to DLL_EXPORT in begin_code.h. (It may also be good
to add an extra BUILD_SDL macro to the table like the OS/2 version..)
Also, the satellite projects such as SDL_mixer should be tested with
the changes.
Comment 3 Philip Bennefall 2020-12-08 19:23:43 UTC 
(In reply to Sam Lantinga from comment #1)
> Fixed, thanks!
> https://hg.libsdl.org/SDL/rev/0aa5690fb1c8
> 
> Also thank you for the heads up on the other patches in that folder. I
> accepted most of them for the next SDL release.

Thank you for the quick turnaround! The string function issue was a blocker for me. Much appreciated!
Comment 4 Ozkan Sezer 2020-12-08 20:19:40 UTC 
(In reply to Ozkan Sezer from comment #2)
> This one https://hg.libsdl.org/SDL/rev/be0a46c9b010 is wrong and also
> problematic.
> 
> The _DLL macro usually is defined by MSVC dll projects, but it is not
> defined by our MSVC project files because it has not been needed. The
> autotools builds define DLL_EXPORT by way of libtool, but begin_code.h
> doesn't check it. The result is: the autotools builds now export all
> and every symbol it can find.
> 
> Solution would be defining DLL_EXPORT in CMake and MSVC project files
> and changing _DLL to DLL_EXPORT in begin_code.h. (It may also be good
> to add an extra BUILD_SDL macro to the table like the OS/2 version..)
> Also, the satellite projects such as SDL_mixer should be tested with
> the changes.

Closing again. Opened a new bug #5384 for this dll exports issue.