Trying to use netlib code (QUADPACK). What is xerror? - fortran

Question

I'm trying to figure out how to use quadpack.
In a single folder, I located the contents of "qag.f plus dependencies" and the code blow as qag_test.f:
(maybe this code itself is not very important. This is in fact just a snippet from the quadpack document)
REAL A,ABSERR,B,EPSABS,EPSREL,F,RESULT,WORK
INTEGER IER,IWORK,KEY,LAST,LENW,LIMIT,NEVAL
DIMENSION IWORK(100),WORK(400)
EXTERNAL F
A = 0.0E0
B = 1.0E0
EPSABS = 0.0E0
EPSREL = 1.0E-3
KEY = 6
LIMIT = 100
LENW = LIMIT*4
CALL QAG(F,A,B,EPSABS,EPSREL,KEY,RESULT,ABSERR,NEVAL,
* IER,LIMIT,LENW,LAST,IWORK,WORK)
C INCLUDE WRITE STATEMENTS
STOP
END
C
REAL FUNCTION F(X)
REAL X
F = 2.0E0/(2.0E0+SIN(31.41592653589793E0*X))
RETURN
END
Using gfortran *.f (installed as MinGW 64bit), I got:
C:\Users\username\AppData\Local\Temp\ccIQwFEt.o:qag.f:(.text+0x1e0): undefined re
ference to `xerror_'
C:\Users\username\AppData\Local\Temp\cc6XR3D0.o:qage.f:(.text+0x83): undefined re
ference to `r1mach_'
(and a lot more of the same r1mach_ error)
It seems r1mach is a part of BLAS (and I don't know why it's not packaged in here but obtained as "auxiliary"), but what is xerror?
How do I properly compile this snippet in my environment, Win7 64bit (hopefully without Cygwin)?
Your help is very much appreciated.

Answer 1

xerror is an error reporting routine. Looking at the way it is called, it appears to use Hollerith constants (the ones where "foo" is written as 3hfoo).
if(ier.ne.0) call xerror(26habnormal return from qag ,
* 26,ier,lvl)
xerror in turn calls xerrwv, passing along the arguments (plus a few more).
This was definitely written before Fortran 77 became widespread.
Your best bet would be to use a compiler which still supports Hollerith constants, pull in all the dependencies (xeerwv has a few more, I don't know why you didn't get them from netlib) and run it through the compiler of your choice. Most compilers, including gfortran, support Hollerith; just ignore the warnings :-)
You will possibly need to modify one routine, that is xerprt. With gfortran, you could write this one as
subroutine xerprt(c,n)
character(len=1), dimension(n) :: c
write (*,'(500A)') c
end subroutine xerprt
and put this one into a separate file so that the compiler doesn't catch the rank violation (I know, I know...)