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diff --git a/man3/INFINITY.3 b/man3/INFINITY.3 new file mode 100644 index 0000000..aa7ea0c --- /dev/null +++ b/man3/INFINITY.3 @@ -0,0 +1,85 @@ +.\" Copyright 2004 Andries Brouwer <aeb@cwi.nl>. +.\" +.\" SPDX-License-Identifier: Linux-man-pages-copyleft +.\" +.TH INFINITY 3 2023-03-30 "Linux man-pages 6.05.01" +.SH NAME +INFINITY, NAN, HUGE_VAL, HUGE_VALF, HUGE_VALL \- floating-point constants +.SH LIBRARY +Math library +.RI ( libm ) +.SH SYNOPSIS +.nf +.BR "#define _ISOC99_SOURCE" " /* See feature_test_macros(7) */" +.B #include <math.h> +.PP +.B INFINITY +.PP +.B NAN +.PP +.B HUGE_VAL +.B HUGE_VALF +.B HUGE_VALL +.fi +.SH DESCRIPTION +The macro +.B INFINITY +expands to a +.I float +constant representing positive infinity. +.PP +The macro +.B NAN +expands to a +.I float +constant representing a quiet NaN +(when supported). +A +.I quiet +NaN is a NaN ("not-a-number") that does not raise exceptions +when it is used in arithmetic. +The opposite is a +.I signaling +NaN. +See IEC 60559:1989. +.PP +The macros +.BR HUGE_VAL , +.BR HUGE_VALF , +.B HUGE_VALL +expand to constants of types +.IR double , +.IR float , +and +.IR "long double" , +respectively, +that represent a large positive value, possibly positive infinity. +.SH STANDARDS +C11. +.SH HISTORY +C99. +.PP +On a glibc system, the macro +.B HUGE_VAL +is always available. +Availability of the +.B NAN +macro can be tested using +.BR "#ifdef NAN" , +and similarly for +.BR INFINITY , +.BR HUGE_VALF , +.BR HUGE_VALL . +They will be defined by +.I <math.h> +if +.B _ISOC99_SOURCE +or +.B _GNU_SOURCE +is defined, or +.B __STDC_VERSION__ +is defined +and has a value not less than 199901L. +.SH SEE ALSO +.BR fpclassify (3), +.BR math_error (7) |