FREXP(P) POSIX Programmer's Manual FREXP(P)
frexp, frexpf, frexpl - extract mantissa and exponent from a double precision number
double frexp(double num, int *exp);
float frexpf(float num, int *exp);
long double frexpl(long double num, int *exp);
These functions shall break a floating-point number num into a normalized fraction and an
integral power of 2. The integer exponent shall be stored in the int object pointed to by
For finite arguments, these functions shall return the value x, such that x has a magni-
tude in the interval [0.5,1) or 0, and num equals x times 2 raised to the power *exp.
If num is NaN, a NaN shall be returned, and the value of *exp is unspecified.
If num is +-0, +-0 shall be returned, and the value of *exp shall be 0.
If num is +-Inf, num shall be returned, and the value of *exp is unspecified.
No errors are defined.
The following sections are informative.
isnan() , ldexp() , modf() , the Base Definitions volume of IEEE Std 1003.1-2001, <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 orig-
inal Standard can be obtained online at http://www.opengroup.org/unix/online.html .
IEEE/The Open Group 2003 FREXP(P)