ceil(), ceilf()

Round up a value to the next integer

Synopsis:

#include <math.h>

double ceil( double x );

float ceilf( float x );

Arguments:

x

The value you want to round.

Library:

libm

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

Description:

The ceil() and ceilf() functions round the value of x up to the next integer (rounding towards the “ceiling”).

Returns:

The smallest integer ≥ x.

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If an error occurs, these functions return 0, but this is also a valid mathematical result. If you want to check for errors, set errno to 0, call the function, and then check errno again. These functions don't change errno if no errors occurred.

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Examples:

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

int main( void )
{
    printf( "%f %f %f %f %f\n", ceil( -2.1 ), 
      ceil( -2. ), ceil( 0.0 ), ceil( 2. ), 
      ceil( 2.1 ) );

    return EXIT_SUCCESS;
}

produces the output:

-2.000000 -2.000000 0.000000 2.000000 3.000000

Classification:

ANSI, POSIX 1003.1

See also:

floor()