HP MLIB for Itanium Linux Version 9.6 Release Note

Known Problems and Workarounds

HP MLIB for Itanium Linux Version 9.6 Release Note16

Note that the option -us (complimentary to -nus) is provided by the compiler but is totally

redundant.

The compiler also allows the option -nus to be applied to specified names rather than all

names in the source file.

The Fortran compiler option, combined with the MLIB provision of both variants of entry

point name, can cause duplicate symbol definitions at link time as the following examples

illustrate.

Itanium®2-based processors

Suppose you write your own Fortran version of the XERBLA subroutine. If you compile with

the Fortran compiler on Itanium®2-based processors using the compiler option -nus, your

xerbla.o object has an entry point xerbla (without the postpended underscore). However, the

Itanium®2-based MLIB libraries were compiled with the -us option, and the entry points

without underscores were added as synonyms to the entry points with underscores. Hence,

the various MLIB Fortran source subprograms that call XERBLA reference them as xerbla_.

Therefore, your xerbla (without the postpended underscore) does not satisfy the Fortran calls

to XERBLA, so the linker accesses xerbla.o from the library. This file contains both entry

points xerbla and xerbla_, and xerbla conflicts with your XERBLA subroutine.

Moreover, the various MLIB C source subprograms that call XERBLA still reference them as

xerbla (without the postpended underscore). It means that both xerbla and xerbla_ entry

points must be provided in your xerbla.o.

Use one of the following workarounds on Itanium®2-based processors if you are compiling

your own Fortran version of XERBLA:

• Compile your Fortran source for XERBLA with -nus and provide both xerbla and xerbla_

entry points.

SUBROUTINE XERBLA (SRNAME,INFO)

ENTRY XERBLA_ (SRNAME,INFO)

...

• For a more generic solution, regardless of the use of -nus, use ALIAS directives and

provide both xerbla and xerbla_ entry points.

ifort -us xerbla.f ... xerbla_

ifort -nus xerbla.f ... xerbla

Table 2 Command Line/Entry Point Relationship (Continued)

Command Line Fragment Entry Point