NAME
isinf — test for
infinity
SYNOPSIS
#include
<math.h>
int isinf(real-floating x);
DESCRIPTION
[CX] 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 POSIX.1-2008 defers to the ISO C standard.
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.
EXAMPLES
None.
APPLICATION USAGE
None.
RATIONALE
None.
FUTURE DIRECTIONS
None.
SEE ALSO
fpclassify(3) , isfinite(3) , isnan(3) , isnormal(3) , signbit(3)
XBD <math.h>
CHANGE HISTORY
First released in Issue 6. Derived from the ISO/IEC 9899:1999 (“ISO C99”) standard.