MODF(3)                                                                 Linux Programmer's Manual                                                                MODF(3)

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)):

       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 loca‐
       tion 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 │
       └──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┴───────────────┴─────────┘

CONFORMING TO
       C99, POSIX.1-2001, POSIX.1-2008.

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

SEE ALSO
       frexp(3), ldexp(3)

                                                                               2021-03-22                                                                        MODF(3)