Math library functions and error checking

[Oliver Laumann]

What is the correct method to check whether an exception (overflow,
invalid arguments, etc.) occurred during the execution of a C math
library function (such as sqrt() or sin())?

Do I have to test the result against NaN, or do I have to check errno
(EDOM)?  If the latter is true, is errno cleared automatically on
success or do I have to clear it before calling the function?

Thanks,
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Oliver Laumann     net at TUB.BITNET     net at tub.cs.tu-berlin.de     net at tub.UUCP