float01.c

来自「开放源码的编译器open watcom 1.6.0版的源代码」· C语言 代码 · 共 43 行

#include "fail.h"
#include <float.h>
#include <math.h>

double d = DBL_MAX;
double e = -DBL_MAX;
double f = DBL_MAX*DBL_EPSILON;

int almost( double v1, double v2 )
{
    return !( fabs( v1 - v2 ) < f );
}

typedef double DBL;
DBL r2_noneg( DBL x );

int main( void )
{
    --d;
    ++d;
    d/=2;
    if( almost( d, (DBL_MAX/2) ) ) fail(__LINE__);
    --e;
    ++e;
    e/=2;
    if( almost( e, -(DBL_MAX/2) ) ) fail(__LINE__);
    if( r2_noneg( 0 ) ) fail(__LINE__);
    _PASS;
}

/* Test for messed up handling of float constants in return statement;
 * see Bugzilla Bug 624. Must be located at end of source file to
 * provoke (or not) error.
 */

DBL r2_noneg( DBL x )
{
    if ( x <= 0.0 )
        return( 0.0 );
    else
        return( floor( 100 * x + .5000001 ) / 100 );
}