HP Fortran Programmer's Guide (September 2007)

Compiling and linking

Linking HP Fortran programs

Chapter 2 81

The disadvantage of linking with a shared library is that it creates a dependency between the

library and the program; both the shared library and the program must always be installed

together on the same system. By contrast, linking with an archive library makes the

executable program independent of the library to which it was linked. Also, programs that

make frequent calls to library routines may run more slowly when linked to shared libraries.

By default, the linker selects the shared version of a library, if one is available; otherwise, it

selects the archive version.

NOTE For libF90, libU77, and libIO77 (Itanium only), archive libraries are

selected by default (see +sharedlibF90, +sharedlibU77, and

+sharedlibIO77 options).

To force the linker to select archive libraries, specify the -Wl,-a,archive option on the f90

command line. f90 passes the arguments to the -Wl option (-a and archive) to the linker.

This option must appear before the names of any libraries also speciﬁed on the command line.

The following command line compiles prog.f90 and links it with the archive versions of the

default libraries as well as with the math library (as speciﬁed by the -lm option):

$ f90 -Wl,-a,archive prog.f90 -lm

For information about the linker’s -a option, see the ld(1) man page. For more information

about shared libraries, see “Creating shared libraries” on page 87.

Library search rules

When you use the -l option to specify the name of a library, the linker searches for the library

in the directories speciﬁed by the LPATH environment variable. The f90 command sets this

variable so that the linker looks ﬁrst in /opt/fortran90/lib, then in /usr/lib. You can

specify another directory to search by setting LPATH yourself; see “LPATH environment

variable” on page 95.

Alternatively, you can use the -L