The Open Group Base Specifications Issue 6
IEEE Std 1003.1, 2004 Edition
Copyright © 2001-2004 The IEEE and The Open Group, All Rights reserved.
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NAME

isfinite - test for finite value

SYNOPSIS

#include <math.h>

int isfinite(real-floating x);

DESCRIPTION

[CX] [Option Start] The functionality described on this reference page is aligned with the ISO C standard. Any conflict between the requirements described here and the ISO C standard is unintentional. This volume of IEEE Std 1003.1-2001 defers to the ISO C standard. [Option End]

The isfinite() macro shall determine whether its argument has a finite value (zero, subnormal, or normal, and not infinite or NaN). First, an argument represented in a format wider than its semantic type is converted to its semantic type. Then determination is based on the type of the argument.

RETURN VALUE

The isfinite() macro shall return a non-zero value if and only if its argument has a finite value.

ERRORS

No errors are defined.

The following sections are informative.

EXAMPLES

None.

APPLICATION USAGE

None.

RATIONALE

None.

FUTURE DIRECTIONS

None.

SEE ALSO

fpclassify(), isinf(), isnan(), isnormal(), signbit(), the Base Definitions volume of IEEE Std 1003.1-2001 <math.h>

CHANGE HISTORY

First released in Issue 6. Derived from the ISO/IEC 9899:1999 standard.

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