frexp(), frexpf()
Break a floating-point number into a normalized fraction and an integral power of 2
Synopsis:
#include <math.h> double frexp( double value, int* exp ); float frexpf( float value, int* exp );
Arguments:
- value
- The value you want to break into a normalized fraction.
- exp
- A pointer to a location where the function can store the integral power of 2.
Library:
libm
Use the -l m option to qcc to link against this library.
Description:
These functions break a floating-point number into a normalized fraction and an integral power of 2. It stores the integral power of 2 in the int pointed to by exp.
Returns:
x, such that x is a double with magnitude in the interval [0.5, 1] or 0, and value equals x times 2 raised to the power exp. If value is 0, then both parts of the result are 0.
Examples:
#include <stdio.h> #include <stdlib.h> #include <math.h> int main( void ) { int expon; double value; value = frexp( 4.25, &expon ); printf( "%f %d\n", value, expon ); value = frexp( -4.25, &expon ); printf( "%f %d\n", value, expon ); return EXIT_SUCCESS; }
produces the output:
0.531250 3 -0.531250 3
Classification:
Safety: | |
---|---|
Cancellation point | No |
Interrupt handler | No |
Signal handler | No |
Thread | Yes |