EXPM1(3) Linux Programmer's Manual EXPM1(3)
expm1, expm1f, expm1l - exponential minus 1
double expm1(double x);
float expm1f(float x);
long double expm1l(long double x);
Link with -lm.
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
expm1(), expm1f(), expm1l(): _BSD_SOURCE || _SVID_SOURCE ||
_XOPEN_SOURCE >= 500 || _ISOC99_SOURCE; or cc -std=c99
expm1(x) returns a value equivalent to
exp(x) - 1
It is computed in a way that is accurate even if the value of x is near
zero--a case where exp(x) - 1 would be inaccurate due to subtraction of
two numbers that are nearly equal.
BSD, C99. The float and long double variants are C99 requirements.
exp(3), log(3), log1p(3)
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