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NAME

       modf, modff, modfl - extract signed integral and fractional values from
       floating-point number

SYNOPSIS

       #include <math.h>

       double modf(double x, double *iptr);
       float modff(float x, float *iptr);
       long double modfl(long double x, long double *iptr);

       Link with -lm.

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

       modf(), modl(): _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 600 ||
       _ISOC99_SOURCE; or cc -std=c99

DESCRIPTION

       The  modf()  function breaks the argument x into an integral part and a
       fractional part, each of which has the same sign as  x.   The  integral
       part is stored in the location pointed to by iptr.

RETURN VALUE

       The modf() function returns the fractional part of x.

       If x is a NaN, a NaN is returned, and *iptr is set to a NaN.

       If x is positive infinity (negative infinity), +0 (-0) is returned, and
       *iptr is set to positive infinity (negative infinity).

ERRORS

       No errors occur.

CONFORMING TO

       C99, POSIX.1-2001.  The variant returning double also conforms to SVr4,
       4.3BSD, C89.

SEE ALSO

       frexp(3), ldexp(3)

COLOPHON

       This  page  is  part of release 3.24 of the Linux man-pages project.  A
       description of the project, and information about reporting  bugs,  can
       be found at http://www.kernel.org/doc/man-pages/.

                                  2008-08-05