HP-UX 11i Version 1.6 Release Notes

Programming
Math Library (libm)
Chapter 7
109
Math Library (libm)
The HP-UX Math Library, libm, supports all mathematical functions specified by the C
standard, ANSI/ISO/IEC 9899:1999 (C99) , as well as functions specified by the XPG4.2,
SVID, and COSE Common API (Spec 1170) specifications.
Summary of Change
The HP-UX 11i v1.6 introduces new functions in the HP-UX namespace:
• reciprocal square root (rsqrt[fwlq])
• integer-exponent power functions (pown[fwlq], powlln[fwlq])
Details of Change
The reciprocal square root functions provide a combined square root and divide, which is
common in some important performance critical applications, with about the execution
time of a square root alone.
The integer-exponent power functions provide a direct C translation of the Fortran real
integer operations, and achieve better performance in some cases than the standard C
pow functions.
Users may call the new functions if they wish, but are not otherwise required to take any
action. (See Compatibility below.)
Impact
No impact.
Compatibility
The names of the new functions expand the HP-UX namespace:
and further with the -fpwidetypes option:
If these names have been for other purposes, the pertinent code may need to be altered.
Table 7-1 New HP-UX Functions
rsqrt rsqrtf rsqrtl
pown pownf pownl
powlln powllnf powllnl
Table 7-2 Further HP-UX Function Expansion
rsqrtw rsqrtq pownw
pownq powllnw powllnq