ierror \*- catch Fortran errors
if ( ierror ( \fIerrno\fB ) .ne. 0 ) goto \fIlabel\fR
provides a way of detecting errors during the running of a Fortran
Its argument is a run-time error number
it returns a 0 value; thus the
statement in the synopsis is not executed.
However, the routine stores inside itself the
call point and invocation level.
If and when the indicated error occurs,
It is a ghastly error to call
has already returned when the error occurs.
This routine is essentially tailored to
catching end-of-file situations.
Typically it is called just before the start
of the loop which reads the input file,
jumps to a graceful termination of the program.
There is a limit of 5 on the number
of different error numbers which can be caught.
There is no way to ignore errors.