modf(3)                    Library Functions Manual                    modf(3)

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

LIBRARY
       Math library (libm, -lm)

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);

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

       modff(), modfl():
           _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
               || /* Since glibc 2.19: */ _DEFAULT_SOURCE
               || /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE

DESCRIPTION
       These functions break 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
       These functions return 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.

ATTRIBUTES
       For an explanation of the terms used in this section, see
       attributes(7).

       +--------------------------------------------+---------------+---------+
       |Interface                                   | Attribute     | Value   |
       +--------------------------------------------+---------------+---------+
       |modf (), modff (), modfl ()                 | Thread safety | MT-Safe |
       +--------------------------------------------+---------------+---------+
STANDARDS
       C11, POSIX.1-2008.

HISTORY
       C99, POSIX.1-2001.

       The variant returning double also conforms to SVr4, 4.3BSD, C89.

SEE ALSO
       frexp(3), ldexp(3)

Linux man-pages 6.7               2023-10-31                           modf(3)