Open System Services System Calls Reference Manual (G06.28+)

System Functions (f - i) gamma_r(2)
If the correct value would cause overflow, HUGE_VAL is returned.
If the correct value would cause underflow, 0.0 (zero) is returned.
ERRORS
If the following condition occurs, the gamma_r() function sets errno to the corresponding
value:
[EDOM] The value of x is 0.0, (zero), a nonpositive integer, or negative infinity.
RELATED INFORMATION
Functions: exp(3), fp_class(3), gamma(3), isnan(3), lgamma(3), lgamma_r(2).
STANDARDS CONFORMANCE
This function is an extension to the UNIX98 specification. Interfaces documented on this refer-
ence page conform to the following industry standards:
• IEEE Std 1003.1c-1995, POSIX System Application Program Interface
The use of the header file spthread.h is an HP exception to the POSIX standard.
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