The other day I have the pleasure of manually typing in some Fortran77 code that was published in 1986. Why? Because it was from a scientific journal and it was only scanned in.

Anyways, I've managed to get the damn thing to compile, but the linker croaks:

ld: /tmp/ifortna84Ki.o: in function `MAIN__':
main.f:(.text+0x6ed): undefined reference to `q_'
ld: main.f:(.text+0x6f9): undefined reference to `q_'
ld: main.f:(.text+0x705): undefined reference to `q_'
ld: main.f:(.text+0x711): undefined reference to `q_'
ld: main.f:(.text+0x71d): undefined reference to `q_'
ld: /tmp/ifortna84Ki.o:main.f:(.text+0x729): more undefined references to `q_' follow

The funny thing is: I've not using any library functions as far as a know, unless you count "SQRT" and the like. Everything is defined in the file.

Granted, the code seems to be using some sort of obscure "VAX FORTRAN 77" dialect, so there were a few things I had to edit to make the thing compile. So who knows?

All I know is: I have no clue how to actually troubleshoot this. If I knew "what" the undefined references were to, I'd be able to reason out what's going wrong. But...`q_' is not particularly helpful.