How to detect unresolved references at compile time?

[codes02]

Assuming a unix like shell

powerpc-wrs-vxworks-readelf -s FRC_UserProgram.out

will list all symbols in your program. The ones marked 'UND' are undefined.

A simple filter for them (not exact, you also only need worry about GLOBAL syms, not LOCAL ones).

powerpc-wrs-vxworks-readelf -s FRC_UserProgram.out | grep UND

A better one (that only prints symbol names):

powerpc-wrs-vxworks-readelf -s FRC_UserProgram.out \
| awk '{ if ($5 == "GLOBAL" && $7 == "UND") print $8 }'

Of course, vxworks provides some of those unresolved symbols, and what is useful to you is determining whether your program uses symbols that vxworks does not provide.

Potentially you could construct a list of symbols provided by vxworks (adding new ones that your code uses as needed), filter those out, and if any are left produce an error in your build scripts.

The following shows how to filter out known vxworks symbols (assuming you list them, 1 per line, in vxworks_syms.txt):

powerpc-wrs-vxworks-readelf -s FRC_UserProgram.out \
 | awk '{ if ($5 == "GLOBAL" && $7 == "UND") print $8 }' \
 | grep -vFf vxworks_syms.txt

Edit: also, sorry that this is not quite compile time . I can't help you there (though -Wmissing-prototypes helps)