Static Build errors

[HawkDeath]

There are problems during static build, about unavailability of symbols in static lib.
There are no hint about necessity of including NN_STATIC_LIB as macro define while building with static linkage.
$ g++ pair.c -pthread -lnanomsg C:\msys64\tmp\ccyDAzLi.o:pair.c:(.text+0x57): undefined reference to `__imp_nn_send' C:\msys64\tmp\ccyDAzLi.o:pair.c:(.text+0x94): undefined reference to `__imp_nn_recv' C:\msys64\tmp\ccyDAzLi.o:pair.c:(.text+0xc7): undefined reference to `__imp_nn_freemsg' C:\msys64\tmp\ccyDAzLi.o:pair.c:(.text+0x10d): undefined reference to `__imp_nn_setsockopt' C:\msys64\tmp\ccyDAzLi.o:pair.c:(.text+0x173): undefined reference to `__imp_nn_socket' C:\msys64\tmp\ccyDAzLi.o:pair.c:(.text+0x1a7): undefined reference to `__imp_nn_bind' C:\msys64\tmp\ccyDAzLi.o:pair.c:(.text+0x1e8): undefined reference to `__imp_nn_shutdown' C:\msys64\tmp\ccyDAzLi.o:pair.c:(.text+0x20d): undefined reference to `__imp_nn_socket' C:\msys64\tmp\ccyDAzLi.o:pair.c:(.text+0x241): undefined reference to `__imp_nn_connect' C:\msys64\tmp\ccyDAzLi.o:pair.c:(.text+0x282): undefined reference to `__imp_nn_shutdown' collect2.exe: error: ld returned 1 exit status

[gdamore]

Yeah, unfortunately we assume that you want to build a DLL by default. Windows is problematic here -- you have to set things up for either a DLL or a static lib, and they aren't handled the same way.

Define -DNN_STATIC_LIB=1 or you can define NNG_DECL=extern -- either will work.

I will review our approach for nng and for future nanomsg releases.

[gdamore]

For now I'll add docs to this effect.

[SG7]

This are the steps to get a static library: (Linux)

1. Download nanomsg stable from: https://github.com/nanomsg/nanomsg/1.0.0.zip.
2. Extract zip file.
3. Rename nanomsg-1.0.0 to nanomsgsrc.
4. Delete 1.0.0.zip
5. Create destination folder beside just-unpacked source folder. You should now have two folders side by side: nanomsgsrc and nanomsglib. 
6. Switch current directory to source folder (nanomsgsrc ).
7. Create a directory named build and switch into this new directory. 
8. Run command: cmake .. -DMAKE_INSTALL_PREFIX=../../nanomsglib/ -DC_BUILD_TYPE=Debug -DNN_STATIC_LIB=1
   DMAKE_INSTALL_PREFIX describes the compilation destination, DC_BUILD_TYPE describes the build type (In this case Debug), and DNN_STATIC_LIB sets the output to static library.
9. Run command: cmake --build && ctest -C Debug.
10. Run: cmake --build . --target install

11. You will now have the static library and include files within the destination folder. The static library will be found at: nanomsglib/lib64/libnanomsg.a , and the include files will be found at: nanomsglib/include.

Or you can use the following script:

#!/bin/bash

#Download nanomsg library 1.0 stable
wget https://github.com/nanomsg/nanomsg/archive/1.0.0.zip

#Extract from archive and delete archive
unzip 1.0.0.zip && rm 1.0.0.zip

#Rename source file
mv nanomsg-1.0.0 nanomsgsrc

#Create destination folder
mkdir nanomsglib

#Switch into nanomsgsrc folder
cd nanomsgsrc

#Create build directory and switch into it
mkdir build && cd build

#Compile
cmake .. -DCMAKE_INSTALL_PREFIX=../../nanomsglib/ -DCMAKE_BUILD_TYPE=Debug -DNN_STATIC_LIB=1
cmake --build .
ctest -C Debug .
cmake --build . --target install