ldexp(), ldexpf(), ldexpl()
Multiply a floating-point number by an integral power of 2
Synopsis:
#include <math.h> double ldexp( double x, int exp ); float ldexp( float x, int exp ); long double ldexpl( long double x, int exp );
Arguments:
- x
- A floating-point number.
- exp
- The exponent of 2 to multiply x by.
Description:
These functions multiply the floating-point number x by 2exp.
A range error may occur.
Returns:
x × 2exp
For a correct value that would cause an underflow, these functions return 0.0.
If an error occurs, these functions return 0, but this is also a valid
mathematical result.
If you want to check for errors, set
errno
to 0, call the function, and then check errno again.
These functions don't change errno if no errors occurred.
Examples:
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
int main( void )
{
double value;
value = ldexp( 4.7072345, 5 );
printf( "%f\n", value );
return EXIT_SUCCESS;
}
produces the output:
150.631504
Classification:
| Safety: | |
|---|---|
| Cancellation point | No |
| Interrupt handler | No |
| Signal handler | No |
| Thread | Yes |