sqrt(3M)

NAME
     sqrt, fsqrt, sqrtf, sqrtl, cbrt, cbrtl - cube root, square root

SYNOPSIS
     #include <math.h>

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

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

IMPLEMENTATION
     IRIX systems

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

     The sqrt functions return the nonnegative square root of their single
     argument x. The function sqrt both accepts and returns values of type
     double.  The functions fsqrt and sqrtf accept and return float values.
     The function sqrtl both accepts and returns values of type long
     double.

     A fast version of sqrt and fsqrt which are slightly less accurate are
     available in the library -lfastm. On MIPS2 and newer processors, those
     routines are identical to the ones in libm.a, because there are
     hardware square root instructions.

     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 result.

     Users concerned with portability to other computer systems should note
     that the long double and float versions of these functions are
     optional according to the ANSI C Programming Language Specification
     ISO/IEC 9899 : 1990 (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 if 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)

     This man page is available only online.