LDEXP(3) | Library Functions Manual | LDEXP(3)

# NAME

`ldexp`, `ldexpf`, `ldexpl` — multiply floating-point number by integral power of 2

# SYNOPSIS

Math Library (libm, -lm)
`#include <math.h>`

double
`ldexp`(double x, int exp);

float
`ldexpf`(float x, int exp);

long double
`ldexpl`(long double x, int exp);

# DESCRIPTION

The `ldexp`() function multiplies a floating-point number by an integral power of 2. The `ldexpf`() function is a single precision version of `ldexp`(). The `ldexpl`() function is an extended precision version of `ldexp`().

# RETURN VALUES

The `ldexp`(), `ldexpf`() and `ldexpl`() functions return the value of x times 2 raised to the power exp.

If the resultant value would cause an overflow, the global variable errno is set to `ERANGE` and the value `HUGE` is returned.

# SEE ALSO

frexp(3), modf(3)

# STANDARDS

The `ldexp`() function conforms to ANSI X3.159-1989 (“ANSI C89”).

June 6, 2025 | Debian