remainder(1) remainder function

Other Alias

remainderf, remainderl


#include <math.h>

double remainder(double x, double y);
float remainderf(float
x, float y);
long double remainderl(long double
x, long double y);


These functions shall return the floating-point remainder r= x- ny when y is non-zero. The value n is the integral value nearest the exact value x/ y. When |n-x/y|=0.5, the value n is chosen to be even.

The behavior of remainder() shall be independent of the rounding mode.


Upon successful completion, these functions shall return the floating-point remainder r= x- ny when y is non-zero.

If x or y is NaN, a NaN shall be returned.

If x is infinite or y is 0 and the other is non-NaN, a domain error shall occur, and either a NaN (if supported), or an implementation-defined value shall be returned.


These functions shall fail if:

Domain Error
The x argument is ±Inf, or the y argument is ±0 and the other argument is non-NaN.

If the integer expression (math_errhandling & MATH_ERRNO) is non-zero, then errno shall be set to [EDOM]. If the integer expression (math_errhandling & MATH_ERREXCEPT) is non-zero, then the invalid floating-point exception shall be raised.

The following sections are informative.




On error, the expressions (math_errhandling & MATH_ERRNO) and (math_errhandling & MATH_ERREXCEPT) are independent of each other, but at least one of them must be non-zero.






Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. In the event of any discrepancy between this version and the original IEEE and The Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can be obtained online at .