The problem with cxref is that it does not accurately find function
definitions. The star gets put on the line number of the first declaration
for the function that it finds, or nowhere at all! I was using it on
PCC itself (an older version) and it was useless. Ctags -x works much
better; out of the couple of hundred functions in pcc, it only omitted
about ten. As far as I know there is NO program which will infallibly
find function definitions in C source.
How about the C compiler?