exp(3) — Linux manual page

exp(3)                  Library Functions Manual                  exp(3)

NAME

       exp, expf, expl - base-e exponential function

LIBRARY

       Math library (libm, -lm)

SYNOPSIS

       #include <math.h>

       double exp(double x);
       float expf(float x);
       long double expl(long double x);

   Feature Test Macro Requirements for glibc (see
   feature_test_macros(7)):

       expf(), expl():
           _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
               || /* Since glibc 2.19: */ _DEFAULT_SOURCE
               || /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE

DESCRIPTION

       These functions return the value of e (the base of natural
       logarithms) raised to the power of x.

RETURN VALUE

       On success, these functions return the exponential value of x.

       If x is a NaN, a NaN is returned.

       If x is positive infinity, positive infinity is returned.

       If x is negative infinity, +0 is returned.

       If the result underflows, a range error occurs, and zero is
       returned.

       If the result overflows, a range error occurs, and the functions
       return +HUGE_VAL, +HUGE_VALF, or +HUGE_VALL, respectively.

ERRORS

       See math_error(7) for information on how to determine whether an
       error has occurred when calling these functions.

       The following errors can occur:

       Range error, overflow
              errno is set to ERANGE.  An overflow floating-point
              exception (FE_OVERFLOW) is raised.

       Range error, underflow
              errno is set to ERANGE.  An underflow floating-point
              exception (FE_UNDERFLOW) is raised.

ATTRIBUTES

       For an explanation of the terms used in this section, see
       attributes(7).
       ┌─────────────────────────────────────┬───────────────┬─────────┐
       │ Interface                           │ Attribute     │ Value   │
       ├─────────────────────────────────────┼───────────────┼─────────┤
       │ exp(), expf(), expl()               │ Thread safety │ MT-Safe │
       └─────────────────────────────────────┴───────────────┴─────────┘

STANDARDS

       C11, POSIX.1-2008.

HISTORY

       C99, POSIX.1-2001.

       The variant returning double also conforms to SVr4, 4.3BSD, C89.

SEE ALSO

       cbrt(3), cexp(3), exp10(3), exp2(3), expm1(3), sqrt(3)

COLOPHON

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Linux man-pages 6.9.1          2024-05-02                         exp(3)

Pages that refer to this page: erf(3), erfc(3), exp10(3), exp2(3), expm1(3), log1p(3)

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