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.Dd January 26, 2005 .Dt FPCLASSIFY 3 .Os .Sh NAME .Nm fpclassify , isfinite , isinf , isnan , isnormal .Nd "classify a floating-point number" .Sh LIBRARY .Lb libm .Sh SYNOPSIS n math.h .Ft int .Fn fpclassify "real-floating x" .Ft int .Fn isfinite "real-floating x" .Ft int .Fn isinf "real-floating x" .Ft int .Fn isnan "real-floating x" .Ft int .Fn isnormal "real-floating x" .Sh DESCRIPTION The .Fn fpclassify macro takes an argument of .Fa x and returns one of the following manifest constants. l -tag -width ".Dv FP_SUBNORMAL" t Dv FP_INFINITE Indicates that .Fa x is an infinite number. t Dv FP_NAN Indicates that .Fa x is not a number (NaN). t Dv FP_NORMAL Indicates that .Fa x is a normalized number. t Dv FP_SUBNORMAL Indicates that .Fa x is a denormalized number. t Dv FP_ZERO Indicates that .Fa x is zero (0 or -0). .El
p The .Fn isfinite macro returns a non-zero value if and only if its argument has a finite (zero, subnormal, or normal) value. The .Fn isinf , .Fn isnan , and .Fn isnormal macros return non-zero if and only if .Fa x is an infinity, NaN, or a non-zero normalized number, respectively.
p The symbol .Fn isnanf is provided as an alias to .Fn isnan for compatibility, and its use is deprecated. Similarly, .Fn finite and .Fn finitef are deprecated versions of .Fn isfinite . .Sh SEE ALSO .Xr isgreater 3 , .Xr math 3 , .Xr signbit 3 .Sh STANDARDS The .Fn fpclassify , .Fn isfinite , .Fn isinf , .Fn isnan , and .Fn isnormal macros conform to .St -isoC-99 . .Sh HISTORY The .Fn fpclassify , .Fn isfinite , .Fn isinf , .Fn isnan , and .Fn isnormal macros were added in .Fx 5.1 . x 3 introduced .Fn isinf and .Fn isnan functions, which accepted .Vt double arguments; these have been superseded by the macros described above.