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If you cannot rebuild libpost.lib using VS2019 and legacy_stdio_definitions.lib does not resolve the symbols then Microsoft suggests wrapping the static library in a DLL.
Linker failure when building using Visual Studio 2019
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Peter Mortimer
1
Reputation point
My project is being moved from Visual Studio 2010 to Visual Studio 2019 and I am trying to evaluate and solve issues. When I build my project using VS2019 I get the following linker errors:
libpost.lib(sucfile.obj) : error LNK2019: unresolved external symbol __daylight referenced in function __totalsec
libpost.lib(sucfile.obj) : error LNK2019: unresolved external symbol __timezone referenced in function __totalsec
libpost.lib(l_getenv.obj) : error LNK2019: unresolved external symbol __environ referenced in function _pXtWgzN5X32ssD34ZpsSW
The libpost.lib is provided by a third party company and I cannot rebuild it or find the source for it. I know that _daylight and _timezone have been deprecated by Microsoft. I have tried to add the legacy_stdio_definitions.lib to my library path but I still get the failures.
I have gone down the route of installing the VS2010 toolset/sdk/compiler which I have success in building with, but company policy is telling me I cannot use unsupported toolsets etc because of potential security issues.
My question is - is there another legacy lib I can include from Microsoft to get around this problem, or has anyone else had a similar problem and know of a workaround.
Thanks in advance, Pete.
Developer technologies Visual Studio Other
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Viorel 122.5K Reputation points2020-10-09T14:28:43.22+00:00 Did you add the legacy_stdio_definitions.lib to “Additional Dependencies” field of Project Properties for all of build configurations and all of projects?
What is the company policy regarding libpost.lib?
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Peter Mortimer 1 Reputation point
2020-10-09T15:12:01.523+00:00 Thanks for your answer.
We are using a make file to do the build and we have as part of our USERLIBRARIES:
USERLIBRARIES = "C:\Program Files (x86)\Microsoft Visual Studio\2019\Professional\VC\Tools\MSVC\14.27.29110\lib\x86\legacy_stdio_definitions.lib"The libpost.lib is supplied by a third party company who have withdrawn support for their product. We cannot get an up to date version and we cannot get the source to recompile it.
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RLWA32 49,536 Reputation points2020-10-09T14:36:12.017+00:00 -
Peter Mortimer 1 Reputation point
2020-10-09T15:14:21.857+00:00 Thanks for the answer. I will look into trying that and get back to you. Pete
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Tianyu Sun-MSFT 34,436 Reputation points Microsoft External Staff2020-10-13T08:14:25.733+00:00 @Peter Mortimer Hi Peter, do you have any update? Feel free to let us know.
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Peter Mortimer 1 Reputation point
2020-10-13T16:49:33.33+00:00 Thank you.
I am trying to create the dll using NMAKE and a makefile .
I am building in a development command prompt.
I have had some success with building the .dll and associated .lib files.
My linking is still failing because the original library is still getting linked.
I need to exclude it somehow. -
RLWA32 49,536 Reputation points
2020-10-13T17:06:35.137+00:00 You need to build the wrapper DLL with the same version of Visual Studio that was used to create the static library (libpost.lib) that you are wrapping. So use VS2010 to create the DLL and its import library.
In the VS2019 project remove all references to the static library and its headers. Use the import library for the DLL. and its exported wrapper functions.
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Peter Mortimer 1 Reputation point
2020-10-14T16:55:28.51+00:00 Thanks for getting back to me.
When I create the wrapper dll do I have to export all the functions/globals in my libpost.lib explicitly using the __declspec(dllexport) attribute?
I do not have any documentation about what is contained in the libpost.lib library. I am only aware of what is failing to link! -
RLWA32 49,536 Reputation points
2020-10-14T17:23:14.55+00:00 Building the DLL with VS2010 should take care of any linking problems with libpost.lib
At a minimum, your DLL should export wrappers for what your VS2019 project needs to function. I assume that if you try to build the VS2019 project but omit providing libpost.lib to the linker the resultant error messages about unresolved symbols should serve as a guide to what needs to be exported by the wrapper DLL. I also assume that you have a header file that contains function prototypes (and maybe other relevant info) for libpost.lib.
Wrapping and exporting additional functions and variables may make sense if you will update other old projects that linked with libpost.lib.
Make sure to heed the MS guidance about not leaking CRT details from VS2010 across the DLL boundary for anything exported by your wrappers.
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