The Open Group Base Specifications Issue 6
IEEE Std 1003.1, 2003 Edition
Copyright © 2001-2003 The IEEE and The Open Group, All Rights reserved.

NAME

isinf - test for infinity

SYNOPSIS

#include <math.h>

int isinf(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 isinf() macro shall determine whether its argument value is an infinity (positive or negative). 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 isinf() macro shall return a non-zero value if and only if its argument has an infinite value.

ERRORS

No errors are defined.

The following sections are informative.

EXAMPLES

None.

APPLICATION USAGE

None.

RATIONALE

None.

FUTURE DIRECTIONS

None.

SEE ALSO

fpclassify() , isfinite() , 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.

End of informative text.
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