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



PPRROOLLOOGG
       This manual page is part of the POSIX Programmer's Manual.  The OS
       implementation of this interface may differ (consult the corresponding
       OS manual page for details of OS behavior), or the interface may not be
       implemented on OS.


NNAAMMEE
       modf, modff, modfl -- decompose a floating-point number

SSYYNNOOPPSSIISS
       #include <math.h>

       double modf(double _x, double *_i_p_t_r);
       float modff(float _v_a_l_u_e, float *_i_p_t_r);
       long double modfl(long double _v_a_l_u_e, long double *_i_p_t_r);

DDEESSCCRRIIPPTTIIOONN
       The functionality described on this reference page is aligned with the
       ISO C standard. Any conflict between the requirements described here
       and the ISO C standard is unintentional. This volume of POSIX.1-2008
       defers to the ISO C standard.

       These functions shall break the argument _x into integral and fractional
       parts, each of which has the same sign as the argument. It stores the
       integral part as a ddoouubbllee (for the _m_o_d_f() function), a ffllooaatt (for the
       _m_o_d_f_f() function), or a lloonngg ddoouubbllee (for the _m_o_d_f_l() function), in the
       object pointed to by _i_p_t_r.

RREETTUURRNN VVAALLUUEE
       Upon successful completion, these functions shall return the signed
       fractional part of _x.

       If _x is NaN, a NaN shall be returned, and *_i_p_t_r shall be set to a NaN.

       If _x is +-Inf, +-0 shall be returned, and *_i_p_t_r shall be set to +-Inf.

EERRRROORRSS
       No errors are defined.

       _T_h_e _f_o_l_l_o_w_i_n_g _s_e_c_t_i_o_n_s _a_r_e _i_n_f_o_r_m_a_t_i_v_e_.

EEXXAAMMPPLLEESS
       None.

AAPPPPLLIICCAATTIIOONN UUSSAAGGEE
       The _m_o_d_f() function computes the function result and *_i_p_t_r such that:

           aa == mmooddff((xx,, iippttrr)) ;;
           xx ==== aa++**iippttrr ;;

       allowing for the usual floating-point inaccuracies.

RRAATTIIOONNAALLEE
       None.

FFUUTTUURREE DDIIRREECCTTIIOONNSS
       None.

SSEEEE AALLSSOO
       _f_r_e_x_p(), _i_s_n_a_n(), _l_d_e_x_p()

       The Base Definitions volume of POSIX.1-2008, <<mmaatthh..hh>>

CCOOPPYYRRIIGGHHTT
       Portions of this text are reprinted and reproduced in electronic form
       from IEEE Std 1003.1, 2013 Edition, Standard for Information Technology
       -- Portable Operating System Interface (POSIX), The Open Group Base
       Specifications Issue 7, Copyright (C) 2013 by the Institute of
       Electrical and Electronics Engineers, Inc and The Open Group.  (This is
       POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) In the
       event of any discrepancy between this version and the original IEEE and
       The Open Group Standard, the original IEEE and The Open Group Standard
       is the referee document. The original Standard can be obtained online
       at http://www.unix.org/online.html .

       Any typographical or formatting errors that appear in this page are
       most likely to have been introduced during the conversion of the source
       files to man page format. To report such errors, see
       https://www.kernel.org/doc/man-pages/reporting_bugs.html .



IEEE/The Open Group                  2013                              MODF(3)
