Can't link using MSVC.

[Julio César Rocha]

Are there any specific instructions to build using MSVC/Visual Studio?

After creating a class that refers to 

  Class1.obj : error LNK2001: unresolved external symbol mallocx [myproject.vcxproj]

  Class1.obj : error LNK2001: unresolved external symbol rallocx [myproject.vcxproj]

  Class1.obj : error LNK2001: unresolved external symbol xallocx [myproject.vcxproj]

  Class1.obj : error LNK2001: unresolved external symbol sallocx [myproject.vcxproj]

  Class1.obj : error LNK2001: unresolved external symbol dallocx [myproject.vcxproj]

  Class1.obj : error LNK2001: unresolved external symbol sdallocx [myproject.vcxproj]

  Class1.obj : error LNK2001: unresolved external symbol nallocx [myproject.vcxproj]

  Class1.obj : error LNK2001: unresolved external symbol mallctl [myproject.vcxproj]

  Class1.obj : error LNK2001: unresolved external symbol mallctlnametomib [myproject.vcxproj]

  Class1.obj : error LNK2001: unresolved external symbol mallctlbymib [myproject.vcxproj]

Tracking the definition for those symbols, MallocImpl.cpp shows:

#ifdef _MSC_VER

// MSVC doesn't have weak symbols, so do some linker magic

// to emulate them. (the magic is in the header)

const char* mallocxWeak = nullptr;

const char* rallocxWeak = nullptr;

const char* xallocxWeak = nullptr;

const char* sallocxWeak = nullptr;

const char* dallocxWeak = nullptr;

const char* sdallocxWeak = nullptr;

const char* nallocxWeak = nullptr;

const char* mallctlWeak = nullptr;

const char* mallctlnametomibWeak = nullptr;

const char* mallctlbymibWeak = nullptr;

... but no concrete definition for mallocx, rallocx, etc.

[Guo Rui]

I'm a new folly user, but as I searched yesterday,

If you're using VS2015 or VS2017, then there is an easy way to start using folly (or many other popular cpp libs) by using vcpkg:

https://blogs.msdn.microsoft.com/vcblog/2016/09/19/vcpkg-a-tool-to-acquire-and-build-c-open-source-libraries-on-windows/

[Julio César Rocha]

Thanks! I'll give it a try.

[Guo Rui]

Sure, good luck, and forgot to mention:

1. After installing vcpkg, the command to install folly is:

vcpkg --triplet x64-windows install folly

we need the --triplet flag since folly is x64 only, the install script ran for nearly 1 hour on my Windows VM, without any manual effort though.

2. Then for VS2017, or msbuild, of course only x64 build are supported if used folly.