A function returning a COMPLEX value cannot be compiled in g77 and
called from gfortran (or vice versa) - doing so results in a segfault
or incorrect results. (See test case below.)
This is a problem, since for the near future g77 and gfortran are
likely to coexist on many systems, and incompatible calling
conventions for F77 code means that libraries like the BLAS will have
to be provided in two flavors (g77 and gfortran) on the same system, a
major headache for users (not to mention distributors).
Note that COMPLEX argument passing seems to be okay (the below test
case works fine if it is switched from a function into a subroutine).
Environment:
System: Linux fftw.org 2.6.3-1-686-smp #2 SMP Tue Feb 24 20:29:08 EST 2004 i686
GNU/Linux
Architecture: i686
host: i686-pc-linux-gnu
build: i686-pc-linux-gnu
target: i686-pc-linux-gnu
configured with: ../configure --prefix=/home/stevenj/gcc4
--enable-languages=c,f95
How-To-Repeat:
Create two files, arg1.f and arg1tst.f, consisting of:
arg1.f:
complex function arg1(x, y)
complex x, y
arg1 = x + y
return
end
arg1tst.f:
program arg1tst
complex x,y,z, arg1
x = cmplx(1.,2.)
y = cmplx(3.,4.)
z = arg1(x,y)
write(*,*) z
end
Compile arg1.f with g77 (I'm using version 3.3.5):
g77 -c arg1.f
Compile arg1tst.f with gfortran, and link with arg1.o from above:
gfortran arg1tst.f arg1.o -o arg1tst
Run ./arg1tst, and the result on my system is:
Segmentation fault
Expected output is: ( 4.000000 , 6.000000 )
--
Summary: COMPLEX function returns incompatible with g77
Product: gcc
Version: 4.0.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: fortran
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: stevenj at fftw dot org
CC: gcc-bugs at gcc dot gnu dot org
GCC build triplet: i686-pc-linux-gnu
GCC host triplet: i686-pc-linux-gnu
GCC target triplet: i686-pc-linux-gnu
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20178
