Linking a static library to a shared library in MSVC causes unresolved symbol

Question

I'm building a dynamic library c which is linked to a static library b .

The static library b is statically linked to the static library a .

The cmake for c , roughly looks like this (the cmakes for a and b are quite similar):

cmake_minimum_required(VERSION 2.6)
project(c)

include_directories(../b/src)
link_directories(../b/Debug)

add_library(c SHARED src/c.cpp)
target_link_libraries(c PRIVATE b)

The issue I'm facing is related to the fact that c can't see references to functions defined in a :

b.lib(b.obj) : error LNK2019: unresolved external symbol "int __cdecl a(void)" (?a@@YAHXZ) referenced in function "int __cdecl b(void)" (?b@@YAHXZ) [C:\Users\user\Workspace\garbage\c\c.vcxproj]
C:\Users\user\Workspace\garbage\c\Debug\c.dll : fatal error LNK1120: 1 unresolved externals [C:\Users\user\Workspace\garbage\c\c.vcxproj]

Is there any way for c to properly link?

Related questions:

Linking static libraries to other static libraries

Answer 1

Something tells me that your linker output is not quite right. It looks like perhaps a and b are trying to be exported classes.

That aside, this line tells us that b cannot actually see some symbol (perhaps the class default constructor) for library (class) a :

b.lib(b.obj) : error LNK2019: unresolved external symbol "int __cdecl a(void)" (?a@@YAHXZ) referenced in function "int __cdecl b(void)" (?b@@YAHXZ)

In fact, your CMake example never links a to b and, your original questions says that b is linked into a . If you mean what you said in your question, you linker shows the logic error.