HP aC++/HP C Programmer's Guide (B3901-90036; A.06.26; September 2011)

With this pragma set to OFF, unsuffixed floating-point constants are treated as having
type double.
With this pragma set to ON, unsuffixed floating-point constants are treated as having
type _Decimal64.
The pragma can occur in either of these two contexts:
• Outside external declarations
In this case, the pragma takes effect from its occurrence until another
FLOAT_CONST_DECIMAL64 pragma is encountered, or until the end of the
translation unit.
• Preceding all explicit declarations and statements inside a compound statement.
In this case, the pragma takes effect from its occurrence until another
FLOAT_CONST_DECIMAL64 pragma is encountered (including within a nested
compound statement), or until the end of the compound statement; at the end of a
compound statement, the state for the pragma is restored to its condition just before
the compound statement.
If this pragma is used in any other context, the behavior is undefined. The default state
for the pragma is OFF.
For more information on using Decimal FP, see the HP aC++/HP ANSI C Release Notes
section "Decimal floating-point arithmetic supported" under "New Features in the A.06.20
Release."
STDC FP_CONTRACT Pragma
#pragma STDC FP_CONTRACT ON
#pragma STDC FP_CONTRACT OFF
This pragma tells the compiler whether or not it is permitted to contract expressions. Also
see ISO/IEC 9899 Standard.
Each pragma can occur either outside external declarations or preceding all explicit
declarations and statements inside a compound statement. When outside external
declarations, the pragma takes effect from its occurrence until another FP_CONTRACT
pragma is encountered, or until the end of the translation unit. When inside a compound
statement, the pragma takes effect from its occurrence until another FP_CONTRACT
pragma is encountered within a nested compound statement, or until the end of the
compound statement. At the end of a compound statement, the state for the pragma is
restored to its condition before the compound statement.
If this pragma is used in any other context, the behavior is undefined. The default state
is ON.
STDC FENV_ACCESS Pragma
#pragma STDC FENV_ACCESS ON
Other Pragmas 133