round, roundf, roundl - round to the nearest integer value in a floating-point format
double round(double x);
float roundf(float x);
long double roundl(long double x);
[CX] 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 round their argument to the nearest integer value in floating-point format, rounding halfway cases away from zero, regardless of the current rounding direction.
Upon successful completion, these functions shall return the rounded integer value. [MX] The result shall have the same sign as x.
[MX] If x is NaN, a NaN shall be returned.
If x is ±0 or ±Inf, x shall be returned.
No errors are defined.
The integral value returned by these functions need not be expressible as an intmax_t. 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.
XBD Treatment of Error Conditions for Mathematical Functions, <math.h>
First released in Issue 6. Derived from the ISO/IEC 9899:1999 standard.
POSIX.1-2008, Technical Corrigendum 1, XSH/TC1-2008/0520  is applied.
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