mirror of https://github.com/mkerrisk/man-pages
93 lines
2.1 KiB
Plaintext
93 lines
2.1 KiB
Plaintext
.\" Copyright (c) 2001-2003 The Open Group, All Rights Reserved
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.TH "NAN" 3P 2003 "IEEE/The Open Group" "POSIX Programmer's Manual"
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.\" nan
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.SH NAME
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nan, nanf, nanl \- return quiet NaN
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.SH SYNOPSIS
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.LP
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\fB#include <math.h>
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.br
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.sp
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double nan(const char *\fP\fItagp\fP\fB);
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.br
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float nanf(const char *\fP\fItagp\fP\fB);
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.br
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long double nanl(const char *\fP\fItagp\fP\fB);
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.br
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\fP
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.SH DESCRIPTION
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.LP
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The function call \fInan\fP("\fIn-char-sequence\fP") shall be equivalent
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to:
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.sp
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.RS
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.nf
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\fBstrtod("NAN(\fP\fIn-char-sequence\fP\fB)", (char **) NULL);
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\fP
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.fi
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.RE
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.LP
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The function call \fInan\fP("") shall be equivalent to:
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.sp
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.RS
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.nf
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\fBstrtod("NAN()", (char **) NULL)
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\fP
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.fi
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.RE
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.LP
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If \fItagp\fP does not point to an \fIn\fP- \fBchar\fP sequence or
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an empty string, the function call shall be equivalent
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to:
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.sp
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.RS
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.nf
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\fBstrtod("NAN", (char **) NULL)
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\fP
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.fi
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.RE
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.LP
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Function calls to \fInanf\fP() and \fInanl\fP() are equivalent to
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the corresponding function calls to \fIstrtof\fP() and \fIstrtold\fP().
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.SH RETURN VALUE
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.LP
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These functions shall return a quiet NaN, if available, with content
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indicated through \fItagp\fP.
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.LP
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If the implementation does not support quiet NaNs, these functions
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shall return zero.
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.SH ERRORS
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.LP
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No errors are defined.
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.LP
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\fIThe following sections are informative.\fP
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.SH EXAMPLES
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.LP
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None.
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.SH APPLICATION USAGE
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.LP
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None.
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.SH RATIONALE
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.LP
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None.
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.SH FUTURE DIRECTIONS
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.LP
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None.
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.SH SEE ALSO
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.LP
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\fIstrtod\fP() , \fIstrtold\fP() , the Base Definitions volume of
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IEEE\ Std\ 1003.1-2001, \fI<math.h>\fP
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.SH COPYRIGHT
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Portions of this text are reprinted and reproduced in electronic form
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from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
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-- Portable Operating System Interface (POSIX), The Open Group Base
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Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
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Electrical and Electronics Engineers, Inc and The Open Group. In the
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event of any discrepancy between this version and the original IEEE and
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The Open Group Standard, the original IEEE and The Open Group Standard
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is the referee document. The original Standard can be obtained online at
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http://www.opengroup.org/unix/online.html .
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