log1pl
Log1pl is the long double variant of the logarithm of one plus x, written as log(1+x) with long double precision. It is part of the C standard library’s math API, typically declared as long double log1pl(long double x) in math.h as part of C99 and later standards. The function is designed to compute the natural logarithm of 1+x with high accuracy when x is near zero, avoiding cancellation that can occur with a naïve computation of log(1+x).
Domain and behavior: log1pl is defined for real x with x > -1, since 1+x must be positive.
Numerical approach: implementations use careful argument handling, often employing range reduction and a polynomial or rational
Availability: log1pl is widely available in major C libraries that provide long double variants of math functions
See also: log1p, log1pf, log1pl. Applications include numerical analysis, statistical computations, and scientific simulations where stable