C/C++ Programmer's Guide (G06.25+)

Compiler Pragmas
HP C/C++ Programmer’s Guide for NonStop Systems—429301-008
13-45
IEEE_FLOAT
IEEE_FLOAT
The IEEE_FLOAT directive specifies that the native C and C++ compilers use the IEEE
floating-point format for performing floating-point operations. Compare to pragma
TANDEM_FLOAT on page 13-102.
The pragma default settings are:
Usage Guidelines
•
The IEEE_FLOAT directive can be entered on the compiler RUN command line or,
in the OSS environment, with the -W IEEE_float flag of the c89 program.
•
To build and run programs using IEEE floating-point format, you need the following
software and hardware:
°
NonStop server with an Itanium processor or NonStop S7000 or S72000 server
(IEEE floating-point format is not available on NonStop S70000 processors)
°
NonStop operating system G07 or later product version
°
G06.06 or later product version of the native C or C++ compiler
°
G06.06 or later product version of the eld, ld, or nld utility for linking
•
You must also specify the VERSION2 directive if you specify IEEE_FLOAT with the
TNS/R native C++ compiler. For more information, see VERSION2 on
page 13-106.
•
If you specify the IEEE_FLOAT directive, you cannot also specify the SQL pragma.
•
Note the following advantages of using IEEE floating-point:
°
IEEE floating-point format has a different range of values and different
precision than Tandem floating-point format.
°
IEEE floating-point format gives faster performance and is easier for porting
native applications than Tandem floating-point format.
IEEE_FLOAT
SYSTYPE GUARDIAN SYSTYPE OSS
TNS C compiler N.A. N.A.
G-series TNS c89 utility N.A. N.A.
TNS/R native C and C++ compilers TANDEM_FLOAT TANDEM_FLOAT
Native c89 utility TNS/R code:
TANDEM_FLOAT
TNS/E code:
IEEE_FLOAT
TNS/R code:
TANDEM_FLOAT
TNS/E code:
IEEE_FLOAT
TNS/E native C and C++ compilers IEEE_FLOAT IEEE_FLOAT