lrint(3p) — Linux manual page

PROLOG | NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | EXAMPLES | APPLICATION USAGE | RATIONALE | FUTURE DIRECTIONS | SEE ALSO | COPYRIGHT

LRINT(3P)               POSIX Programmer's Manual              LRINT(3P)

PROLOG         top

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

NAME         top

       lrint, lrintf, lrintl — round to nearest integer value using
       current rounding direction

SYNOPSIS         top

       #include <math.h>

       long lrint(double x);
       long lrintf(float x);
       long lrintl(long double x);

DESCRIPTION         top

       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 nearest integer
       value, rounding according to the current rounding direction.

       An application wishing to check for error situations should set
       errno to zero and call feclearexcept(FE_ALL_EXCEPT) before
       calling these functions. On return, if errno is non-zero or
       fetestexcept(FE_INVALID | FE_DIVBYZERO | FE_OVERFLOW |
       FE_UNDERFLOW) is non-zero, an error has occurred.

RETURN VALUE         top

       Upon successful completion, these functions shall return the
       rounded integer value.

       If x is NaN, a domain error shall occur and an unspecified value
       is returned.

       If x is +Inf, a domain error shall occur and an unspecified value
       is returned.

       If x is -Inf, a domain error shall occur and an unspecified value
       is returned.

       If the correct value is positive and too large to represent as a
       long, an unspecified value shall be returned.  On systems that
       support the IEC 60559 Floating-Point option, a domain error shall
       occur; otherwise, a domain error may occur.

       If the correct value is negative and too large to represent as a
       long, an unspecified value shall be returned.  On systems that
       support the IEC 60559 Floating-Point option, a domain error shall
       occur; otherwise, a domain error may occur.

ERRORS         top

       These functions shall fail if:

       Domain Error
                   The x argument is NaN or ±Inf, or the correct value
                   is not representable as an integer.

                   If the integer expression (math_errhandling &
                   MATH_ERRNO) is non-zero, then errno shall be set to
                   [EDOM].  If the integer expression (math_errhandling
                   & MATH_ERREXCEPT) is non-zero, then the invalid
                   floating-point exception shall be raised.

       These functions may fail if:

       Domain Error
                   The correct value is not representable as an integer.

                   If the integer expression (math_errhandling &
                   MATH_ERRNO) is non-zero, then errno shall be set to
                   [EDOM].  If the integer expression (math_errhandling
                   & MATH_ERREXCEPT) is non-zero, then the invalid
                   floating-point exception shall be raised.

       The following sections are informative.

EXAMPLES         top

       None.

APPLICATION USAGE         top

       On error, the expressions (math_errhandling & MATH_ERRNO) and
       (math_errhandling & MATH_ERREXCEPT) are independent of each
       other, but at least one of them must be non-zero.

RATIONALE         top

       These functions provide floating-to-integer conversions. They
       round according to the current rounding direction. If the rounded
       value is outside the range of the return type, the numeric result
       is unspecified and the invalid floating-point exception is
       raised. When they raise no other floating-point exception and the
       result differs from the argument, they raise the inexact
       floating-point exception.

FUTURE DIRECTIONS         top

       None.

SEE ALSO         top

       feclearexcept(3p), fetestexcept(3p), llrint(3p)

       The Base Definitions volume of POSIX.1‐2017, Section 4.20,
       Treatment of Error Conditions for Mathematical Functions,
       math.h(0p)

COPYRIGHT         top

       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                         LRINT(3P)

Pages that refer to this page: math.h(0p)llrint(3p)