Name
modf, modff, modfl - extract signed integral and fractional values from floating-point numberLibrary
Math library ( libm ", " -lm )Synopsis
#include <math.h> double modf(double " x ", double * iptr );
float modff(float " x ", float * iptr );
long double modfl(long double " x ", long double * iptr );
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
modff() modfl()
_ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L || /* Since glibc 2.19: */ _DEFAULT_SOURCE || /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
Description
These functions break the argument x into an integral part and a fractional part, each of which has the same sign asx
. The integral part is stored in the location pointed to by iptr
. Return Value
These functions return the fractional part ofx
. 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).
Errors
No errors occur.Attributes
For an explanation of the terms used in this section, see attributes(7).Interface | Attribute | Value |
T} | Thread safety | MT-Safe |
Standards
C11, POSIX.1-2008.History
C99, POSIX.1-2001.The variant returning double also conforms to SVr4, 4.3BSD, C89.