[ 2018-06-18 after reflector discussion ]

Priority set to 3

[sf.cmath]/1 uses the phrase "report a domain error" (emphasis mine):

If any argument value to any of the functions specified in this subclause is a NaN (Not a Number), the function shall return a NaN but it shall not report a domain error. Otherwise, the function shall report a domain error for just those argument values for which:

• the function description's Returns: clause explicitly specifies a domain and those argument values fall outside the specified domain, or

• the corresponding mathematical function value has a nonzero imaginary component, or

• the corresponding mathematical function is not mathematically defined.

The behavior this phrase is attempting to convey is unclear. A quick search through the text of the standard for "domain error" finds only the domain_error exception type defined in [domain.error]. Is the intent of "report a domain error" that the special math functions throw an exception of type domain_error, or is it that they behave as specified in C11 7.12.1 "Treatment of error conditions" para 2 which defines the term "domain error"?