modf, modff, modfl - extract signed integral and fractional values from
floating-point number
#include <math.h>
double modf(double x, double *iptr);
float modff(float x, float *iptr);
long double modfl(long double x, long double *iptr);
Link with
-lm.
Feature Test Macro Requirements for glibc (see
feature_test_macros(7)):
modf(),
modfl():
_ISOC99_SOURCE ||
_POSIX_C_SOURCE >= 200112L
|| /* Since glibc 2.19: */ _DEFAULT_SOURCE
|| /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
These functions break the argument
x into an integral part and a
fractional part, each of which has the same sign as
x. The integral
part is stored in the location pointed to by
iptr.
These functions return the fractional part of
x.
If
x is a NaN, a NaN is returned, and
*iptr is set to a NaN.
If
x is positive infinity (negative infinity), +0 (-0) is returned, and
*iptr is set to positive infinity (negative infinity).
No errors occur.
For an explanation of the terms used in this section, see
attributes(7).
| Interface |
Attribute |
Value |
| modf (), modff (), modfl () |
Thread safety |
MT-Safe |
C99, POSIX.1-2001, POSIX.1-2008.
The variant returning
double also conforms to SVr4, 4.3BSD, C89.
frexp(3),
ldexp(3)