[Bug fortran/71412] iso_c_bindings and optimization interaction bug

["sgk at troutmask dot apl.washington.edu" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71412

--- Comment #5 from Steve Kargl <sgk at troutmask dot apl.washington.edu> ---
On Sat, Jun 04, 2016 at 04:36:24PM +0000, relliott at umn dot edu wrote:
> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71412
> 
> --- Comment #4 from relliott at umn dot edu ---
> > Ahem, give val the SAVE attribute.
> >
> >  integer(c_int), pointer, save :: val
> 
> Hi,  Thanks for your help.  Unfortunately, I don't think using
> save will serve my purpose in this case.  Although, now I see
> that the skeleton code does not illustrate this aspect of my
> requirements.  The myalloc() function is supposed 
> to be able to allocate multiple independent values.

Have you considered the SAVE attribute?

  integer(c_int), pointer,save    :: val

laptop-kargl:kargl[246] gmake
gfc -O3 -g -Wall -pedantic  -c skeleton-f.F90
~/work/bin/gcc -O3 -g -Wall -ansi -pedantic  -c skeleton-c.c
gfc -O3 -g -Wall skeleton*.o  -o skeleton
laptop-kargl:kargl[247] ./skeleton 
 -- in storePtr: pointer address --> 0x28621018 <-- value --> 0 <-- index --> 0
 -- just a print statement --> nothing <-- index -->           0
 -- in getPtr:   pointer address --> 0x28621018 <-- value --> 21 <-- index -->
0
 -- in storePtr: pointer address --> 0x28621020 <-- value --> 0 <-- index --> 1
 -- just a print statement --> nothing <-- index -->           1
 -- in getPtr:   pointer address --> 0x28621020 <-- value --> 12 <-- index -->
1
 -- value of 'val0' variable -->           21
 -- value of 'val1' variable -->           12

PS: You probably do not want to use -pedantic with gfortran.

PPS: bugzilla is not an appropriate forum to learn Fortran.  Try 
comp.lang.fortran.