March 10, 1994 IEEE_TEST 3

### NAME

logb, logbf, scalb, scalbf, significand, significandf - IEEE test functions

### LIBRARY

Math Library (libm, -lm)

### SYNOPSIS

```double` logb(```double x`)
```float` logbf(```float x`)
```double` scalb(```double x``, double n`)
```float` scalbf(```float x``, float n`)
```double` significand(```double x`)
```float` significandf(```float x`)

### DESCRIPTION

These functions allow users to test conformance to IEEE Std 754-1985 . Their use is not otherwise recommended.

logb(```x`) returns ```x`'s exponent ```n`, a signed integer converted to double-precision floating-point. logb(``) = +; logb(```0`) = - with a division by zero exception.

scalbn(```x``, n`) returns ```x`*(2**```n`) computed by exponent manipulation.

significand(```x`) returns ```sig`, where ```x` := ```sig` * 2**```n` with 1 ```sig` < 2. significand(```x`) is not defined when ```x` is 0, , or .

### SEE ALSO

ieee(3), math(3)

### STANDARDS

IEEE Std 754-1985