Link errors when building shared library even though source files are included - dll

Question

I am specifying a shared library build from source files in my CMakeLists.txt file like so:
# Library setup
file(GLOB_RECURSE SOURCES ${CMAKE_CURRENT_SOURCE_DIR}/Source/*.cpp)
file(GLOB_RECURSE HEADERS ${CMAKE_CURRENT_SOURCE_DIR}/Source/*.h)
Inside the source directories contain all my .h and .cpp files required to build my shared library. So I then do something like this:
add_library(mylibrary SHARED ${SOURCES} ${HEADERS} )
I also link a bunch of other .libs with mylibrary later on as well (Could there be a clashing issue?). The problem arises when I try to build mylibrary. I receive linking errors such as:
Severity Code Description Project File Line Suppression State
Error LNK2001 unresolved external symbol __imp_cosf mylibrary ***.obj 1
even though the symbol is defined in my source files that I have included. I am not exactly sure what to do in order to properly let my project find those symbols. The funny thing is is that when I build as a static library it is fine. However, when I try to build as a dynamic library, these errors appear.

Answer 1

So, I'm not exactly sure why this worked. But there was a conflict warning between linking to MSVRCT and libcmt. It said something like this in the output log:
Resolving LNK4098: defaultlib 'MSVCRT' conflicts with ...
This is because libcmt is a static library for release build and uses \MT flags. MSVRCT is a release DLL version and compiled with \MD flag. Because of this conflict, I had to change my compiler flags to be:
set(CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE} /MT")
set(CMAKE_CXX_FLAGS_DEBUG "${CMAKE_CXX_FLAGS_DEBUG} /MTd")
Then the symbols were able to be found. If anyone has any comments/corrections to why this worked please add.