# round(), roundf(), roundl()

Round a number to the closest integer

## Synopsis:

```#include <math.h>

double round( double x );

float roundf( float x );

long double roundl( long double x );
```

## Arguments:

x
The number you want to round.

## Library:

libm

Use the -l m option to qcc to link against this library.

## Description:

The round(), roundf(), and roundl() functions return x rounded to the nearest integer n, rounding halfway cases away from zero, regardless of the current rounding direction (i.e., returning the value with larger magnitude if |nx| == 1/2).

To check for error situations, use feclearexcept() and fetestexcept(). For example:

• Call feclearexcept(FE_ALL_EXCEPT) before calling round(), roundf(), or roundl().
• On return, if fetestexcept(FE_ALL_EXCEPT) is nonzero, then an error has occurred.

## Returns:

The rounded value.

If x is: rint() returns: Errors:
±Inf x
NaN x

These functions raise FE_INEXACT if the FPU reports that the result can't be exactly represented as a floating-point number.

## Examples:

```#include <math.h>
#include <stdio.h>
#include <stdlib.h>
#include <fenv.h>

int main (void)
{
int except_flags;
double num1, result1;

for (num1 = 3.0; num1 <= 4.0; num1 += 0.1)
{
feclearexcept(FE_ALL_EXCEPT);
result1 = round (num1);
except_flags = fetestexcept(FE_ALL_EXCEPT);
if (except_flags) {
/* An error occurred; handle it appropriately. */
} else {
printf ("Rounding %f gives %f\n", num1, result1);
}
}

return (EXIT_SUCCESS);
}
```

## Classification:

Safety:
Cancellation point No
Interrupt handler No
Signal handler No