mirror of https://github.com/mkerrisk/man-pages
89 lines
2.6 KiB
Groff
89 lines
2.6 KiB
Groff
.\" Copyright 2004 Andries Brouwer <aeb@cwi.nl>.
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.\"
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.\" Permission is granted to make and distribute verbatim copies of this
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.\" manual provided the copyright notice and this permission notice are
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.\" preserved on all copies.
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.\"
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.\" Permission is granted to copy and distribute modified versions of this
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.\" manual under the conditions for verbatim copying, provided that the
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.\" entire resulting derived work is distributed under the terms of a
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.\" permission notice identical to this one.
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.\"
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.\" Since the Linux kernel and libraries are constantly changing, this
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.\" manual page may be incorrect or out-of-date. The author(s) assume no
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.\" responsibility for errors or omissions, or for damages resulting from
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.\" the use of the information contained herein. The author(s) may not
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.\" have taken the same level of care in the production of this manual,
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.\" which is licensed free of charge, as they might when working
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.\" professionally.
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.\"
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.\" Formatted or processed versions of this manual, if unaccompanied by
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.\" the source, must acknowledge the copyright and authors of this work.
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.\"
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.TH FINITE 3 2004-10-31 "" "Linux Programmer's Manual"
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.SH NAME
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finite, finitef, finitel, isinf, isinff, isinfl, isnan, isnanf, isnanl \-
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BSD floating point classification functions
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.SH SYNOPSIS
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.nf
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#define _BSD_SOURCE
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.br
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.B #include <math.h>
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.sp
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.BI "int finite(double " x );
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.br
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.BI "int finitef(float " x );
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.br
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.BI "int finitel(long double " x );
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.sp
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.BI "int isinf(double " x );
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.br
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.BI "int isinff(float " x );
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.br
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.BI "int isinfl(long double " x );
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.sp
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.BI "int isnan(double " x );
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.br
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.BI "int isnanf(float " x );
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.br
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.BI "int isnanl(long double " x );
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.fi
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.SH DESCRIPTION
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The
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.BR finite ()
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functions return a non-zero value if \fIx\fP is neither infinite
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nor a "not-a-number" (NaN) value, and 0 otherwise.
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The
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.BR isnan ()
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functions return a non-zero value if \fIx\fP is a NaN value,
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and 0 otherwise.
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The
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.BR isinf ()
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functions return 1 if \fIx\fP is plus infinity, \-1 is \fIx\fP
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is minus infinity, and 0 otherwise.
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.SH NOTES
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Note that these functions are obsolete.
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C99 defines macros
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isfinite(), isinf() and isnan() (for all types) replacing them.
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Further note that the C99 isinf() has weaker guarantees on the return value.
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See
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.BR fpclassify (3).
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.\"
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.\" finite* not on HP-UX; they exist on Tru64.
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.SH AVAILABILITY
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On a glibc system, these functions are declared by
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.I <math.h>
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when _BSD_SOURCE or _SVID_SOURCE or _GNU_SOURCE is defined.
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The isnan() functions will also be declared when _XOPEN_SOURCE
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is defined.
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.SH HISTORY
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The
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.BR finite ()
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function occurs in 4.3BSD.
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.\" see IEEE.3 in the 4.3BSD manual
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.SH "SEE ALSO"
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.BR fpclassify (3),
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.BR feature_test_macros (7)
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