HP Fortran Programmer's Guide (B3908-90031; September 2011)

Compiling and linking
Compiling with the f90 command
Chapter 240
+[no]fp_exception
+fp_exception is a compile time flag. It causes a descriptive message and a
procedure traceback to be issued to standard error when the HP-UX signals listed in
Table 2-5 are generated.
For a description of these signals, see signal(2) and signal(5) in the HP-UX
Reference. For information about floating-point exceptions and error handling, see the
HP-UX Floating-Point Guide.
You can also use the ON statement to write your own trap procedures. For information
about the syntax of the ON statement, see “Using the ON statement” on page 127.
The default, +nofp_exception, disables traceback information.
-g
D Enable sudden underflow (flush to zero) of denormalized values on
those PA-RISC systems greater than version 1.0 that have
implemented sudden underflow. (That is, +FPD enables sudden
underflow only if it is available on the processor that is used at run
time.) Denormalized values are those values whose absolute value is
very close to zero. For IEEE single precision data types, the largest
denormalized value is approximately equal to 2
-126
. For IEEE double
precision data types, such values are approximately equal to 2
-1022
.
Sudden underflow will cause some floating-point applications to run
faster, with a possible loss of numerical accuracy on numbers very
close to zero.
Table 2-5 Signals recognized by the +fp_exception option
Signal Meaning
SIGILL Illegal instruction
SIGFPE Floating-point exception
SIGBUS Bus error instruction
SIGSEGV Segmentation violation
SIGSYS Bad argument to system call
Table 2-4 Values for the +FP option (Continued)
Value Meaning