-qdfp

Pragma equivalent

None.

Purpose

Enables compiler support for decimal floating-point types and literals.

Syntax


        .-nodfp-.   
>>- -q--+-dfp---+----------------------------------------------><

Defaults

-qnodfp

Usage

If you enable -qdfp for a -qarch value that does not support decimal floating-point instructions, -qfloat=dfpemulate is automatically enabled, and the decimal floating-point operations are performed by software. This may cause a slowdown in the application's runtime performance.

Note: To use decimal floating-point types and literals, you must also enable specific code in header files by defining the __STDC_WANT_DEC_FP__ macro at compile time. See Examples.

Predefined macros

When -qdfp is in effect, __IBM_DFP__ is predefined to a value of 1; otherwise it is undefined.

Examples

To compile myprogram.c that contains decimal floating-point type and literal, enter:

xlc myprogram.c -qarch=pwr7 -qdfp -D__STDC_WANT_DEC_FP__