TRUNC(3)                   POSIX Programmer's Manual                  TRUNC(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
       trunc, truncf, truncl -- round to truncated integer value

SSYYNNOOPPSSIISS
       #include <math.h>

       double trunc(double _x);
       float truncf(float _x);
       long double truncl(long double _x);

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.1-2017
       defers to the ISO C standard.

       These functions shall round their argument to the integer value, in
       floating format, nearest to but no larger in magnitude than the
       argument.

RREETTUURRNN VVAALLUUEE
       Upon successful completion, these functions shall return the truncated
       integer value.
       The result shall have the same sign as _x.

       If _x is NaN, a NaN shall be returned.

       If _x is +-0 or +-Inf, _x shall be returned.

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 integral value returned by these functions need not be expressible
       as an iinnttmmaaxx__tt.  The return value should be tested before assigning it
       to an integer type to avoid the undefined results of an integer
       overflow.

       These functions may raise the inexact floating-point exception if the
       result differs in value from the argument.

RRAATTIIOONNAALLEE
       None.

FFUUTTUURREE DDIIRREECCTTIIOONNSS
       None.

SSEEEE AALLSSOO
       The Base Definitions volume of POSIX.1-2017, <<mmaatthh..hh>>

CCOOPPYYRRIIGGHHTT
       Portions of this text are reprinted and reproduced in electronic form
       from IEEE Std 1003.1-2017, Standard for Information Technology --
       Portable Operating System Interface (POSIX), The Open Group Base
       Specifications Issue 7, 2018 Edition, Copyright (C) 2018 by the
       Institute of Electrical and Electronics Engineers, Inc and The Open
       Group.  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.opengroup.org/unix/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                  2017                             TRUNC(3)
