|RINT(3)||Linux Programmer's Manual||RINT(3)|
NAMEnearbyint, nearbyintf, nearbyintl, rint, rintf, rintl - round to nearest integer
double nearbyint(double x );
float nearbyintf(float x );
long double nearbyintl(long double x );
double rint(double x );
float rintf(float x );
long double rintl(long double x );
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
_XOPEN_SOURCE >= 600 || _POSIX_C_SOURCE >= 200112L || _ISOC99_SOURCE;or cc -std=c99
_BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 500 || _XOPEN_SOURCE && _XOPEN_SOURCE_EXTENDED || _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L;or cc -std=c99
_BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 600 || _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L;or cc -std=c99
DESCRIPTIONThe nearbyint() functions round their argument to an integer value in floating-point format, using the current rounding direction (see fesetround(3)) and without raising the inexact exception.
The rint() functions do the same, but will raise the inexact exception ( FE_INEXACT, checkable via fetestexcept(3)) when the result differs in value from the argument.
RETURN VALUEThese functions return the rounded integer value.
ERRORSNo errors occur. POSIX.1-2001 documents a range error for overflows, but see NOTES.
CONFORMING TOC99, POSIX.1-2001.
NOTESSUSv2 and POSIX.1-2001 contain 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).)
SEE ALSOceil(3), floor(3), lrint(3), round(3), trunc(3)
COLOPHONThis page is part of release 3.53 of the Linux man-pages project. A description of the project, and information about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.