sqrt(3M)

NAME
     cbrt, sqrt, cbrtf, sqrtf, cbrtl, sqrtl, csqrt, csqrtf, csqrtl - cube
     root, square root

SYNOPSIS
     #include <math.h>

     double cbrt(double x);
     float cbrtf(float x);
     long double cbrtl(long double x);

     double sqrt(double x);
     float sqrtf(float x);
     long double sqrtl(long double x);

     #include <complex.h>
     double complex csqrt(double complex z);
     float complex csqrtf(float complex z);
     long double complex csqrtl(long double complex z);

DESCRIPTION
     The functions in the complex.h library are not available for programs
     compiled with the O32 ABI.

     The single-precision and long double-precision routines listed above
     are only available in the standard math library, -lm, and in -lmx.

     Alternate entries exist for several routines.  The following lists
     these routines and the ANSI standard name and the alternate entry
     name:

     ANSI standard name       Alternate name

     sqrtf                    fsqrt

     cbrtl                    qcbrt

     sqrtl                    qsqrt

     The sqrt functions return the nonnegative square root of their single
     argument x.

     The cbrt functions return the cube root of their single argument x.
     The function cbrt both accepts and returns values of type double.  The
     function cbrtl both accepts and returns values of type long double.

RETURN VALUES
     Functions in the standard math library libm.a, are referred to as -lm
     versions. Those in math library libmx.a are referred to as -lmx
     versions. Those in the the BSD math library libm43.a are referred to
     as -lm43 versions. The -lm and -lmx versions always return the default
     Quiet NaN and set errno to EDOM when a NaN is used as an argument.  A
     NaN argument usually causes the -lm43 versions to return the same
     argument.  The -lm43 versions never set errno.

     If x is negative, the sqrt functions return a quiet NaN. The -lm and
     -lm43 versions also set the flag in the floating-point coprocessor to
     indicate an invalid operation.  The functions in the standard math
     library -lm and in library -lmx also set errno to EDOM.

     See matherr(3M) for a description of error handling for -lmx
     functions.

NOTES
     Long double operations on this system are only supported in round-to-
     nearest rounding mode (the default).  The system must be in round-to-
     nearest rounding mode when calling any of the long double functions,
     or incorrect answers will result.

     Users concerned with portability to other computer systems should note
     that the long double and float versions of these functions were
     optional according to the ANSI C Programming Language Specification
     ISO/IEC 9899 : 1990 (E) and are no longer optional according to
     ISO/IEC 9899: 1999 (E).

     Long double functions have been renamed to be compliant with the
     ANSI-C standard, however to be backward compatible, they may still be
     called with the double precision function name prefixed with a q.

     Code which calls sqrt() or sqrtf() will be compiled into the machine
     instruction sqrt.d or sqrt.s if the code uses #includes <math.h>.

   Errors
     cbrt is accurate to within 0.7 ULPs (a ULP is one Unit in Last Place).

     libm.a sqrt conforms to IEEE 754 and is correctly rounded in
     accordance with the rounding mode in force; the error is less than
     half a ULP in the default mode (round to nearest).

     The libfastm.a sqrt and fsqrt error is a maximum of one ULP.  (See
     however, the comments regarding -lfastm above.)

SEE ALSO
     math(3M)