isnan.3

来自「<B>Digital的Unix操作系统VAX 4.2源码</B>」· 3 代码 · 共 16 行

.TH isnan 3
.SH Name
isnan \- test for NaN
.SH Syntax
.B #include <math.h>
.PP
.B int isnan (\fIx\fP)
.br
.B double \fIx\fP;
.SH Description
The
.PN isnan
function returns 1 if \fIx\fP is NaN (the IEEE floating point reserved
not-a-number value) and zero otherwise.  On VAX, the return value is
always zero.