[Bug libfortran/24576] Fortran I/O to same unit number in main program and in a shared library

["iwan at irs dot phy dot nrc dot ca" <gcc-bugzilla at gcc dot gnu dot org>]

------- Comment #5 from iwan at irs dot phy dot nrc dot ca  2005-10-29 01:52 -------
Subject: Re:  Fortran I/O to same unit number in main program and in a shared
library


I guess, it all comes down to what is a "program".
If I look at section 5.5.2.3 of the 2003 Standard about common blocks, 
I find that 
"Within a program, the common block storage sequences of of all 
non-zero sized common blocks with the same name have the same 
first storage unit...".
Yet, if I have common/a/ in some subroutine and create a 
shared library using -Wl,-Bsymbolic (or whatever linker options 
are needed to make symbols local to the shared library), 
this is not the same common block as common/a/ in the main 
program using the shared library. Therefore, if one takes the standard 
seriously, the shared library is not part of the program in this case 
and therefore I/O in the shared library should not interfere with 
I/O in the main program.
This is the behavior one gets with the Intel and PGI compilers on 
Linux and this is the behavior I remember from years ago on 
IRIX and SunOS workstations.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24576