roundf(3)


NAME

   round, roundf, roundl - round to nearest integer, away from zero

SYNOPSIS

   #include <math.h>

   double round(double x);
   float roundf(float x);
   long double roundl(long double x);

   Link with -lm.

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

   round(), roundf(), roundl():
       _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L

DESCRIPTION

   These functions round x to the nearest integer, but round halfway cases
   away from zero (regardless  of  the  current  rounding  direction,  see
   fenv(3)), instead of to the nearest even integer like rint(3).

   For example, round(0.5) is 1.0, and round(-0.5) is -1.0.

RETURN VALUE

   These functions return the rounded integer value.

   If x is integral, +0, -0, NaN,  or infinite, x itself is returned.

ERRORS

   No  errors  occur.  POSIX.1-2001 documents a range error for overflows,
   but see NOTES.

VERSIONS

   These functions first appeared in glibc in version 2.1.

ATTRIBUTES

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

   ┌────────────────────────────┬───────────────┬─────────┐
   │InterfaceAttributeValue   │
   ├────────────────────────────┼───────────────┼─────────┤
   │round(), roundf(), roundl() │ Thread safety │ MT-Safe │
   └────────────────────────────┴───────────────┴─────────┘

CONFORMING TO

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

NOTES

   POSIX.1-2001  contains  text  about  overflow (which might set errno to
   ERANGE, or raise an FE_OVERFLOW exception).  In  practice,  the  result
   cannot overflow on any current machine, so this error-handling stuff is
   just nonsense.  (More precisely, overflow  can  happen  only  when  the
   maximum  value  of  the exponent is smaller than the number of mantissa
   bits.  For the  IEEE-754  standard  32-bit  and  64-bit  floating-point
   numbers  the maximum value of the exponent is 128 (respectively, 1024),
   and the number of mantissa bits is 24 (respectively, 53).)

   If you want to store the rounded value in an integer type, you probably
   want to use one of the functions described in lround(3) instead.

SEE ALSO

   ceil(3), floor(3), lround(3), nearbyint(3), rint(3), trunc(3)

COLOPHON

   This  page  is  part of release 4.09 of the Linux man-pages project.  A
   description of the project, information about reporting bugs,  and  the
   latest     version     of     this    page,    can    be    found    at
   https://www.kernel.org/doc/man-pages/.

                              2016-03-15                          ROUND(3)





Opportunity


Personal Opportunity - Free software gives you access to billions of dollars of software at no cost. Use this software for your business, personal use or to develop a profitable skill. Access to source code provides access to a level of capabilities/information that companies protect though copyrights. Open source is a core component of the Internet and it is available to you. Leverage the billions of dollars in resources and capabilities to build a career, establish a business or change the world. The potential is endless for those who understand the opportunity.

Business Opportunity - Goldman Sachs, IBM and countless large corporations are leveraging open source to reduce costs, develop products and increase their bottom lines. Learn what these companies know about open source and how open source can give you the advantage.





Free Software


Free Software provides computer programs and capabilities at no cost but more importantly, it provides the freedom to run, edit, contribute to, and share the software. The importance of free software is a matter of access, not price. Software at no cost is a benefit but ownership rights to the software and source code is far more significant.


Free Office Software - The Libre Office suite provides top desktop productivity tools for free. This includes, a word processor, spreadsheet, presentation engine, drawing and flowcharting, database and math applications. Libre Office is available for Linux or Windows.





Free Books


The Free Books Library is a collection of thousands of the most popular public domain books in an online readable format. The collection includes great classical literature and more recent works where the U.S. copyright has expired. These books are yours to read and use without restrictions.


Source Code - Want to change a program or know how it works? Open Source provides the source code for its programs so that anyone can use, modify or learn how to write those programs themselves. Visit the GNU source code repositories to download the source.





Education


Study at Harvard, Stanford or MIT - Open edX provides free online courses from Harvard, MIT, Columbia, UC Berkeley and other top Universities. Hundreds of courses for almost all major subjects and course levels. Open edx also offers some paid courses and selected certifications.


Linux Manual Pages - A man or manual page is a form of software documentation found on Linux/Unix operating systems. Topics covered include computer programs (including library and system calls), formal standards and conventions, and even abstract concepts.