pow__ii

Paul Gilbert pgilbert@bank-banque-canada.ca
Wed, 20 Jan 1999 12:04:04 -0500


> R code works but the shared objects built from fortran code do not find
> the appropriate libs with functions like  __pow_ii or __epx at runtime.

I used to have endless trouble with  __pow_ii which as I recall could be be
fixed by the correct incantation of the mix of compiler libraries and
LD_LIBRARY_PATH. It seemed to be extremely sensitive and never easy to get
right. The problem is that pow_ii is not used by R itself, and so when your
fortran code does something like 4**2 (or using variables declared as integer)
then a call to pow_ii is generated and you need to find the correct library. I
eventually fixed the problem by changing the fortran code to 4.0D0**2 (or
4.0D0**2.0D0 ? and declared variables as double). This generates  calls to a
routine which is used by R itself, and I never had to worry about the libraries
again.

This also worked better with Splus, which can also be problematic in this
regard. I highly recommend this change to anyone distributing fortran code with
a package.

I'm not sure about __epx.

Paul Gilbert

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