mirror of https://github.com/mkerrisk/man-pages
71 lines
2.4 KiB
Groff
71 lines
2.4 KiB
Groff
.\" Copyright (C) 2001 Andries Brouwer <aeb@cwi.nl>
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.\"
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.\" %%%LICENSE_START(VERBATIM)
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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.\" manual page may be incorrect or out-of-date.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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.\" %%%LICENSE_END
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.\"
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.\" Text fragments inspired by Martin Schulze <joey@infodrom.org>.
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.\"
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.TH ASPRINTF 3 2013-06-21 "GNU" "Linux Programmer's Manual"
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.SH NAME
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asprintf, vasprintf \- print to allocated string
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.SH SYNOPSIS
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.BR "#define _GNU_SOURCE" " /* See feature_test_macros(7) */"
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.br
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.B #include <stdio.h>
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.sp
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.BI "int asprintf(char **" strp ", const char *" fmt ", ...);"
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.sp
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.BI "int vasprintf(char **" strp ", const char *" fmt ", va_list " ap );
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.SH DESCRIPTION
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The functions
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.BR asprintf ()
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and
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.BR vasprintf ()
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are analogs of
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.BR sprintf (3)
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and
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.BR vsprintf (3),
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except that they allocate a string large enough to hold the output
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including the terminating null byte (\(aq\\0\(aq),
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and return a pointer to it via the first argument.
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This pointer should be passed to
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.BR free (3)
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to release the allocated storage when it is no longer needed.
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.SH RETURN VALUE
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When successful, these functions return the number of bytes printed,
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just like
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.BR sprintf (3).
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If memory allocation wasn't possible, or some other error occurs,
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these functions will return \-1, and the contents of
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.I strp
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is undefined.
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.SH CONFORMING TO
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These functions are GNU extensions, not in C or POSIX.
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They are also available under *BSD.
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The FreeBSD implementation sets
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.I strp
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to NULL on error.
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.SH SEE ALSO
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.BR free (3),
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.BR malloc (3),
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.BR printf (3)
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