.SH SYNOPSIS
.nf
.B #include <math.h>
-.PP
+.P
.BI "int isgreater(" x ", " y );
.BI "int isgreaterequal(" x ", " y );
.BI "int isless(" x ", " y );
.BI "int islessgreater(" x ", " y );
.BI "int isunordered(" x ", " y );
.fi
-.PP
+.P
.RS -4
Feature Test Macro Requirements for glibc (see
.BR feature_test_macros (7)):
.RE
-.PP
+.P
.nf
All functions described here:
_ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
fail if one of the operands is NaN.
This will cause an exception.
To avoid this, C99 defines the macros listed below.
-.PP
+.P
These macros are guaranteed to evaluate their arguments only once.
The arguments must be of real floating-point type (note: do not pass
integer values as arguments to these macros, since the arguments will
.BR isunordered ()
return the result of the relational comparison;
these macros return 0 if either argument is a NaN.
-.PP
+.P
.BR isunordered ()
returns 1 if
.I x