remainder, remainderf, remainderl
<math.h>
<tgmath.h>
remainderl is called. Otherwise, if any argument has integer type or has type double, remainder is called. Otherwise, remainderf is called.The IEEE floating-point remainder of the division operation x/y calculated by this function is exactly the value x - n * y, where the value n is the integral value nearest the exact value x/y. When |n-x/y| = 1⁄2, the value n is chosen to be even.
In contrast to fmod() , the returned value is not guaranteed to have the same sign as x.
If the returned value is 0, it will have the same sign as x.
[edit] Parameters
[edit] Return value
If successful, returns the IEEE floating-point remainder of the division x/y as defined above.
If a domain error occurs, an implementation-defined value is returned (NaN where supported).
If a range error occurs due to underflow, the correct result is returned.
If y is zero, but the domain error does not occur, zero is returned.
[edit] Error handling
Errors are reported as specified in math_errhandling.
Domain error may occur if y is zero.
If the implementation supports IEEE floating-point arithmetic (IEC 60559),
- The current rounding mode has no effect.
- FE_INEXACT is never raised, the result is always exact.
- If x is ±∞ and y is not NaN, NaN is returned and FE_INVALID is raised.
- If y is ±0 and x is not NaN, NaN is returned and FE_INVALID is raised.
- If either argument is NaN, NaN is returned.
[edit] Notes
POSIX requires that a domain error occurs if x is infinite or y is zero.
fmod , but not remainder is useful for doing silent wrapping of floating-point types to unsigned integer types: (0.0 <= (y = fmod (rint (x), 65536.0)) ? y : 65536.0 + y) is in the range [-0.0, 65535.0], which corresponds to unsigned short, but remainder(rint (x), 65536.0) is in the range [-32767.0, +32768.0], which is outside of the range of signed short.
[edit] Example
#include <fenv.h> #include <math.h> #include <stdio.h> // #pragma STDC FENV_ACCESS ON int main(void) { printf ("remainder(+5.1, +3.0) = %.1f\n", remainder(5.1, 3)); printf ("remainder(-5.1, +3.0) = %.1f\n", remainder(-5.1, 3)); printf ("remainder(+5.1, -3.0) = %.1f\n", remainder(5.1, -3)); printf ("remainder(-5.1, -3.0) = %.1f\n", remainder(-5.1, -3)); // special values printf ("remainder(-0.0, 1.0) = %.1f\n", remainder(-0.0, 1)); printf ("remainder(+5.1, Inf) = %.1f\n", remainder(5.1, INFINITY)); // error handling feclearexcept (FE_ALL_EXCEPT ); printf ("remainder(+5.1, 0) = %.1f\n", remainder(5.1, 0)); if (fetestexcept (FE_INVALID )) puts (" FE_INVALID raised"); }
Output:
remainder(+5.1, +3.0) = -0.9 remainder(-5.1, +3.0) = 0.9 remainder(+5.1, -3.0) = -0.9 remainder(-5.1, -3.0) = 0.9 remainder(+0.0, 1.0) = 0.0 remainder(-0.0, 1.0) = -0.0 remainder(+5.1, Inf) = 5.1 remainder(+5.1, 0) = -nan FE_INVALID raised
[edit] References
- C23 standard (ISO/IEC 9899:2024):
- 7.12.10.2 The remainder functions (p: TBD)
- 7.25 Type-generic math <tgmath.h> (p: TBD)
- F.10.7.2 The remainder functions (p: TBD)
- C17 standard (ISO/IEC 9899:2018):
- 7.12.10.2 The remainder functions (p: 185-186)
- 7.25 Type-generic math <tgmath.h> (p: 272-273)
- F.10.7.2 The remainder functions (p: 385)
- C11 standard (ISO/IEC 9899:2011):
- 7.12.10.2 The remainder functions (p: 254-255)
- 7.25 Type-generic math <tgmath.h> (p: 373-375)
- F.10.7.2 The remainder functions (p: 529)
- C99 standard (ISO/IEC 9899:1999):
- 7.12.10.2 The remainder functions (p: 235)
- 7.22 Type-generic math <tgmath.h> (p: 335-337)
- F.9.7.2 The remainder functions (p: 465)
[edit] See also
(function) [edit]