October 29, 2003 ISNORMAL 3

### NAME

isnormal - test for normal value

### LIBRARY

Standard C Library (libc, -lc)

### SYNOPSIS

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

### DESCRIPTION

The isnormal(``) macro determines whether its argument ```x` has a normal value. An argument represented in a format wider than its semantic type is converted to its semantic type first. The determination is then based on the type of the argument.

#### IEEE 754

It is determined whether the value of ```x` is normal, and neither zero, subnormal, infinite nor NaN.

#### VAX

It is determined whether the value of ```x` is finite, and neither true zero, dirty zero nor ROP.

### RETURN VALUES

The isnormal(``) macro returns a non-zero value if the value of ```x` is finite. Otherwise 0 is returned.

### ERRORS

No errors are defined.

### SEE ALSO

fpclassify(3), isfinite(3), math(3), signbit(3)

### STANDARDS

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