HP Fortran Programmer Guide (766160-001, March 2014)

• A PA-RISC processor name—for example, PA7100or PA8000.
• portable—code that is compatible across all models. Use +DAportableonly if you want
to ensure that your program will run on different models.
Use the uname -mcommand to learn the model of your machine, as follows:
$ uname
-m 9000/879
Alternatively, you can use the grep command to look up the model number in the file /opt/
langtools/lib/sched.modelsand find its architecture type, as follows:
$ grep 879 /opt/langtools/lib/sched.models
PA80002.0879
You can also use the +DSmodeloption to specify an architecture-specific instruction scheduler,
where model has the same meaning as it does for the +DAoption. Like the +DAoption, the +DSoption
is unnecessary if the program will run on the same machine as you use to compile it. Also, if you
compile with +DAmodel, the compiler will select the scheduling algorithm based on the same
architecture—unless you use the +DSoption to specify a different architecture.
NOTE: Code generated for PA1.1 systems will execute on PA2.0 systems, but the reverse is not
true: the loader will not allow PA2.0 code to run on a PA1.1 system.
Creating shared libraries
As mentioned in “Linking to shared libraries” (page 53), many of the HP-UX as well as HP Fortran
libraries are available in shared as well as archive versions. Linking with shared libraries can make
the executable program smaller and can ensure that it always has the most current version of the
library.
You can make shared versions of your own libraries, using the +piccommand-line option and the
-blinker option. The following sections describe how to use these options and show an example
of how to create a shared library.
Compiling with +pic
The +picoption causes the compiler to generate Position- Independent Code (PIC) for use in a
shared library. PIC contains no absolute addresses and can therefore be placed anywhere in a
process’s address space without addresses having to be relocated. This characteristic of PIC makes
it shareable by multiple processes.
The syntax of the +pic option is:
+pic={short|long|no}
Although compiling with either +pic=short or +pic=longwill generate PIC, in general you
should use the +pic=shortoption. If the linker issues an error message saying that the number
of referenced symbols in the shared library exceeds its limit, recompile with +pic=long, which
will cause the compiler to allocate space for a longer symbol table.
The +pic=no is the default, which causes the compiler to generate absolute code, such as you
would want for executable programs.
The following command line creates three object files—x.o, y.o, and z.o; the code in each file
will be PIC:
$ f90 -c +pic=short x.f90 y.f90 z.f90
For more information about the +picoption, see the HP Fortran Programmer’s Reference.
Special-purpose compilations 59