error message

[paul starr]

Sorrry to bother you, but I am trying to get gfortran going on my macbook
running EL CAPITAN.  I haven't graduated beyond f77, so I wrote an
extremely simply test program, which just sums integers from 1 to 100.
When I try to compile, using
gfortran -o test test.f

or similar command, I get the following error message:

undefined symbols for architecture x86_64.  "start" references from -u
command line option

Can you help?

Dan Purrington