Open System Services Library Calls Reference Manual (G06.28+, H06.05+)

OSS Library Calls (i - m) modf(3)
STANDARDS CONFORMANCE
This function conforms to the XPG4 Version 2 specication with extensions when used for IEEE
oating-point format data. This function conforms to the XPG4 Version 2 specication without
extensions when used for Tandem oating-point data.
The XPG4 Version 2 specication leaves some features to the implementing vendor to dene.
The following features are affected in the HP implementation:
For IEEE oating-point data, errno is not set to [EDOM] when the value of value is
NaN.
errno is not set to [ERANGE] when the result would underow.
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