exp(3M)                        DG/UX R4.11MU05                       exp(3M)


NAME
       exp, expf, cbrt, log, logf, log10, log10f, pow, powf, sqrt, sqrtf -
       exponential, logarithm, power, square root functions

SYNOPSIS
       cc [flag ...] file ...  -lm [library ...]

       #include <math.h>

       double exp (double x);

       float expf (float x);

       double cbrt (double x);

       double log (double x);

       float logf (float x);

       double log10 (double x);

       float log10f (float x);

       double pow (double x, double y);

       float powf (float x, float y);

       double sqrt (double x);

       float sqrtf (float x);

DESCRIPTION
       exp and expf return ex.

       cbrt returns the cube root of x.

       log and logf return the natural logarithm of x.  The value of x must
       be positive.

       log10 and log10f return the base ten logarithm of x.  The value of x
       must be positive.

       pow and powf return xy.  If x is 0, y must be non-negative.  If x is
       negative, y must be an integer.

       sqrt and sqrtf return the non-negative square root of x.  The value
       of x must be positive.

       Those functions using float arguments, expf, logf, log10f, powf, and
       sqrtf will give unpredictable results when used with the -Xt
       compilation option.  In traditional compilation mode float arguments
       are promoted to doubles.  An object compiled with -Xt will expect
       this promotion and therefore not work correctly with these functions.


   Considerations for Threads Programming
                     +---------+-----------------------------+
                     |         |                      async- |
                     |function | reentrant   cancel   cancel |
                     |         |             point     safe  |
                     +---------+-----------------------------+
                     |cbrt     |     Y         N        N    |
                     |exp      |     Y         N        N    |
                     |expf     |     Y         N        N    |
                     |log      |     Y         N        N    |
                     |log10    |     Y         N        N    |
                     |log10f   |     Y         N        N    |
                     |logf     |     Y         N        N    |
                     |pow      |     Y         N        N    |
                     |powf     |     Y         N        N    |
                     |sqrt     |     Y         N        N    |
                     |sqrtf    |     Y         N        N    |
                     +---------+-----------------------------+

DIAGNOSTICS
       exp and expf return HUGE when the correct value would overflow, or 0
       when the correct value would underflow, and set errno to ERANGE.

       When the -Xt compilation option is used, log, logf, log10, and log10f
       return -HUGE and set errno to EDOM when x is negative.  In addition,
       a message indicating DOMAIN error is printed on the standard error
       output.  When x is zero, these routines return -HUGE and set errno to
       EDOM.  In addition, a message indicating SING error is printed on the
       standard error output.

       When the -Xa or -Xc compilation options are used, log, logf, log10,
       and log10f return IEEE NaN, raise an invalid operation exception,
       and set errno to EDOM when x is negative.  When x is zero, these
       routines return -HUGE-VAL, raise a divide by zero exception,  and set
       errno to EDOM.

       When the -Xt compilation option is used, pow and powf return 0 and
       set errno to EDOM when x is zero and y is negative, when x is
       negative and y is not an integer, or when both x and y are zero.  In
       addition, a message indicating DOMAIN error is printed on standard
       error.

       When the -Xa or -Xc compilation options are used, pow and powf return
       HUGE_VAL, raise a divide by zero exception, and set errno to EDOM
       when x is zero and y is negative.  When x is zero and y is a negative
       odd integer, these routines return ±HUGE_VAL, depending upon the sign
       of x , raise a divide by zero exception, and set errno to EDOM.  When
       x is zero and y is a negative even integer, pow and powf return
       HUGE_VAL, raise a divide by zero exception, and set errno to EDOM.
       When x is negative and y is not an integer, these routines return
       IEEE NaN, raise an invalid operation exception, and set errno to
       EDOM.  When both x and y are zero, pow and powf return 1 with no
       error.

       When the correct value for pow or powf would overflow or underflow,
       these functions return ±HUGE or 0, respectively, and set errno to
       ERANGE.

       When the -Xt compilation option is used, sqrt and sqrtf return 0 and
       set errno to EDOM when x is negative.  In addition, a message
       indicating DOMAIN error is printed on standard error.

       When the -Xa or -Xc compilation options are used, sqrt and sqrtf
       return IEEE NaN, raise an invalid operation exception, and set errno
       to EDOM when x is negative.

       For each of these functions, if any argument is a quiet NaN, that
       value is returned.  If any argument is a signaling NaN, a quiet NaN
       is returned and an invalid operation exception is raised.  In either
       case, errno is set to EDOM, and a message indicating DOMAIN error is
       printed on the standard error output.  The only exception is that pow
       and powf return 1 when y is zero, regardless of the value of x

       When the -Xt compilation option is used, these error-handling
       procedures may be changed with the function matherr.  When the -Xa or
       -Xc compilation options are used, HUGE_VAL is returned instead of
       HUGE and no error messages are printed.

SEE ALSO
       cc(1), reentrant(3), hypot(3M), matherr(3M), fpsetmask(3C), sinh(3M).


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