ISIS Frequently Asked Questions

Q1. How do I compile ISIS on a Mac?
Q2. ISIS fails with an error message that mentions ``undefined symbol: _gfortran_copy_string''. What's wrong?
Q3. Why did ISIS compilation fail with undefined reference errors?

A1. See the Mac-specific install page.

A2. The problem here is that two different, incompatible Fortran compilers have been used. The most common situation is that HEASOFT was compiled with gfortran-4.1 or an older version, while ISIS was compiled with a much newer version of gfortran. This is a problem because gfortran-4.1 is binary incompatible with newer versions of gfortran. To avoid such problems, it is important to use a matching set of compilers to build everything. The compilers supported by HEAsoft should also work for isis. Use the same compilers to build both HEAsoft and ISIS.

A3. For example:

gfortran -g -O2 -o /tmp/isis/src/objs/isis -Wl,-export-dynamic ...
/usr/local/lib/libpgplot.so: undefined reference to `e_wsfe'
/usr/local/lib/libpgplot.so: undefined reference to `s_rsfe'
/usr/local/lib/libpgplot.so: undefined reference to `s_cmp'
/usr/local/lib/libpgplot.so: undefined reference to `do_uio'
/usr/local/lib/libpgplot.so: undefined reference to `e_rsfe'
/usr/local/lib/libpgplot.so: undefined reference to `f_inqu'
/usr/local/lib/libpgplot.so: undefined reference to `e_rsue'
/usr/local/lib/libpgplot.so: undefined reference to `i_indx'
/usr/local/lib/libpgplot.so: undefined reference to `do_fio'
/usr/local/lib/libpgplot.so: undefined reference to `e_wsfi'
/usr/local/lib/libpgplot.so: undefined reference to `s_cat'
/usr/local/lib/libpgplot.so: undefined reference to `s_stop'
/usr/local/lib/libpgplot.so: undefined reference to `s_wsfi'
/usr/local/lib/libpgplot.so: undefined reference to `G77_getenv_0'
/usr/local/lib/libpgplot.so: undefined reference to `s_rsue'
/usr/local/lib/libpgplot.so: undefined reference to `f_clos'
/usr/local/lib/libpgplot.so: undefined reference to `f_open'
/usr/local/lib/libpgplot.so: undefined reference to `s_wsfe'
/usr/local/lib/libpgplot.so: undefined reference to `s_copy'
collect2: ld returned 1 exit status

The problem here is an incompatibility between two different Fortran compilers; libpgplot.so was compiled with g77 (note the undefined reference to G77_setenv_0) but you're using gfortran to build isis. To avoid such problems, it is important to use a matching set of compilers to build everything. The compilers supported by HEAsoft should also work for isis. Use the same compilers to build both HEAsoft and ISIS.