January 14, 2004 FPCLASSIFY 3

### NAME

fpclassify - classify real floating type

### LIBRARY

Standard C Library (libc, -lc)

### SYNOPSIS

```int` fpclassify(```real-floating x`)

### DESCRIPTION

The fpclassify(``) macro performs classification of its argument ```x`. An argument represented in a format wider than its semantic type is converted to its semantic type first. The classification is then based on the type of the argument.

#### IEEE 754

```FP_INFINITE`
  infinity, either positive or negative
```FP_NAN`
  not-a-number (``NaN'')
```FP_NORMAL`
  normal
```FP_SUBNORMAL`
  subnormal
```FP_ZERO`
  zero

#### VAX

```FP_ROP`
  reserved operand (``ROP'')
```FP_DIRTYZERO`
  dirty zero
```FP_NORMAL`
  finite
```FP_ZERO`
  true zero

### RETURN VALUES

The fpclassify(``) macro returns the value of the number classification macro appropriate to its argument ```x` as described above.

### ERRORS

No errors are defined.

### SEE ALSO

isfinite(3), isnormal(3), math(3), signbit(3)

### STANDARDS

The fpclassify(``) macro conforms to ISO/IEC 9899:1999 (``ISO C99'') .