The following error occurs when building a Gen 8.6 GUI C client load module which contains External Action Block (EABs)
error LNK2019: unresolved external symbol _zzzzzzzzz referenced in function _f_22020202
_fprintf and _sprintf are examples of unresolved external symbols being reported.
Gen 8.6 Build Tool
The EAB C source code contains deprecated Microsoft C functions so the LOC.EXTERNAL_LIB will need to include special libraries from Microsoft.
In the Build Tool, for the profile being used under Profile Manager, section 'C' add the full PATH of the library file 'legacy_stdio_definitions.lib' to LOC.EXTERNAL_LIB.
For example for Visual Studio 2019, the location is:"C:\Program Files (x86)\Microsoft Visual Studio\2019\Professional\VC\Tools\MSVC\14.27.29110\lib\x86\legacy_stdio_definitions.lib"
There may be other entries needed in LOC.EXTERNAL_LIB depending on the EAB C code.