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fmod, fmodf, fmodl - floating-point remainder value function

#include <math.h>

double fmod(doublex, doubley);

float fmodf(floatx, floaty);

long double fmodl(long doublex, long doubley);

These functions shall return the floating-point remainder of the division of

xbyy.An application wishing to check for error situations should set

errnoto zero and callfeclearexcept(FE_ALL_EXCEPT) before calling these functions. On return, iferrnois non-zero orfetestexcept(FE_INVALID | FE_DIVBYZERO | FE_OVERFLOW | FE_UNDERFLOW) is non-zero, an error has occurred.

These functions shall return the value

x-i*y, for some integerisuch that, ifyis non-zero, the result has the same sign asxand magnitude less than the magnitude ofy.If the correct value would cause underflow, and is not representable, a range error may occur, and either 0.0 (if supported), or an implementation-defined value shall be returned.

If

xoryis NaN, a NaN shall be returned.If

yis zero, a domain error shall occur, and either a NaN (if supported), or an implementation-defined value shall be returned.If

xis infinite, a domain error shall occur, and either a NaN (if supported), or an implementation-defined value shall be returned.If

xis ±0 andyis not zero, ±0 shall be returned.If

xis not infinite andyis ±Inf,xshall be returned.If the correct value would cause underflow, and is representable, a range error may occur and the correct value shall be returned.

These functions shall fail if:

If the integer expression (math_errhandling & MATH_ERRNO) is non-zero, then

Domain Error The xargument is infinite oryis zero.If the integer expression (math_errhandling & MATH_ERRNO) is non-zero, then errnoshall be set to [EDOM]. If the integer expression (math_errhandling & MATH_ERREXCEPT) is non-zero, then the invalid floating-point exception shall be raised.

These functions may fail if: Range Error The result underflows. errnoshall be set to [ERANGE]. If the integer expression (math_errhandling & MATH_ERREXCEPT) is non-zero, then the underflow floating-point exception shall be raised.

The following sections are informative.

None.

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.

None.

None.

feclearexcept() ,fetestexcept() ,isnan() , the Base Definitions volume of IEEE Std 1003.1-2001, Section 4.18, Treatment of Error Conditions for Mathematical Functions,<math.h>

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 http://www.opengroup.org/unix/online.html .

IEEE/The Open Group |
FMOD (P) | 2003 |