Before you run the nsqlprep precompiler, do the following:
·The nsqlprep precompiler uses your compiler to process header files
SET INCLUDE = C\Mssql17\DevTools\INCLUSE; %include%
SET LIB = C\Mssql17\DevTools\LIB; %LIB%
The nsqlprep precompiler automatically includes these header files in the C programs it creates. Do not explicitly include them (by using #include) in an Embedded SQL program.