Shared libraries on AIX

[Steve Edwards]

Hi,

I ran into a slight difficulty with shared libraries on IBM AIX
systems using libtool 2.2.6 (I'm not even sure if this is really
where I should be asking questions about this)

If I have a main Fortran routine containing a common block and call a
Fortran subroutine in a shared library also referencing this common
block, the values in the common block were not being inherited in the
subroutine (Fortran common blocks across shared libraries may
not be ideal, but I was testing something out thinking about libltdl).

I did however find that manually adding -brtl to LDFLAGS allowed this
to work. The documentation I had available stated that -brtl is used
to "determine which algorithm will be used to find libraries", however
there was more info on the ibm site which cleared up some confusion
for me.

Should libtool be adding this flag, or is this something I should
be manually adding via AM_LDFLAGS? Every other aspect of the shared
library build is handled fine by libtool.

If anyone has any suggestions on this I would be grateful to hear
them.

A secondary problem (while trying to do something particularly
non-standard I suspect) was to access Fortran common blocks from
within shared library C routines, but that does not appear to be
anything to do with libtool.

If anyone is interested I have available a cut down test case to
duplicate what happens.

Steve
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