EXP(3M-SVR4)        RISC/os Reference Manual         EXP(3M-SVR4)



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

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

     cc -O -Ksd [flag ...] file ...  -J sfm [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 positive.  If
     x is negative, y must be an integer.

     sqrt and sqrtf return the non-negative square root of x.
     The value of x may not be negative.





                        Printed 11/19/92                   Page 1

EXP(3M-SVR4)        RISC/os Reference Manual         EXP(3M-SVR4)



SEE ALSO
     hypot(3M), matherr(3M), sinh(3M).

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

     log, logf, log10, and log10f return -HUGE and set errno to
     EDOM when x is non-positive.  A message indicating DOMAIN
     error is printed on standard error.

     pow and powf return 0 and set errno to EDOM when x is 0 and
     y is non-positive, or when x is negative and y is not an
     integer.  In these cases, a message indicating DOMAIN error
     is printed on standard 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.

     sqrt and sqrtf return 0 and set errno to EDOM when x is
     negative.  A message indicating DOMAIN error is printed on
     standard error.

     Except when the -Xc 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.  In these compilation modes, pow and powf
     return 1, with no error, when both x and y are 0; when x is
     0 and y is negative, they return -HUGE_VAL and set errno to
     EDOM. Under -Xc, log and logf return -HUGE_VAL and set errno
     to ERANGE when x is 0.  Under -Xc, sqrt and sqrtf return NaN
     when x is negative.






















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