Category
Pragma equivalent
None.
Purpose
Enables compiler support for decimal floating-point types and literals.
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 that runtime support for decimal floating-point operations is available only on AIX® for POWER® version 5.3 with the 5300-06 Technology Level or later. If you enable -qdfp on a version of the operating system that does not provide runtime support, your application will compile, but it may not link or run.
Programs that use decimal floating-point functions or macros defined in the <math.h> include file should not be compiled on AIX 5.2 or on older levels of AIX 5.3 or 5.4. because those functions and macros won't be retrofitted into 5.2.
Predefined macros
When -qdfp is in effect, __IBM_DFP__ is predefined to a value of 1; otherwise it is undefined.