function
<cmath> <ctgmath>
nexttoward
double nexttoward (double x , long double y); float nexttowardf (float x , long double y);long double nexttowardl (long double x, long double y);
double nexttoward (double x , long double y); float nexttoward (float x , long double y);long double nexttoward (long double x, long double y); double nexttoward (T x , long double y); // additional overloads
Next representable value toward precise value
Returns the next representable value after x in the direction of y.
This function behaves as nextafter, but with a potentially more precise y.
Header
<tgmath.h> provides a type-generic macro version of this function.
Additional overloads are provided in this header (
<cmath>) for the
integral types: These overloads effectively cast
x to a
double before calculations (defined for
T being any
integral type).
Parameters
- x
- Base value.
- y
- Value toward which the return value is approximated.
If both parameters compare equal, the function returns y (converted to the return type).
Return Value
The next representable value after x in the direction of y.
If x is the largest finite value representable in the type, and the result is infinite or not representable, an overflow range error occurs.
If an overflow range error occurs:
- And math_errhandling has MATH_ERRNO set: the global variable errno is set to ERANGE.
- And math_errhandling has MATH_ERREXCEPT set: FE_OVERFLOW is raised.
Example
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/* nexttoward example */
#include <stdio.h> /* printf */
#include <math.h> /* nexttoward */
int main ()
{
printf ("first representable value greater than zero: %e\n", nexttoward(0.0,1.0L));
printf ("first representable value less than zero: %e\n", nexttoward(0.0,-1.0L));
return 0;
}
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Possible output:
first representable value greater than zero: 4.940656e-324
first representable value less than zero: -4.940656e-324
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See also
- nextafter
- Next representable value (function)