view buf_reserve.3 @ 13:3e1c384e0d3f

buf_puts: uses memcpy as it may be optimized
author David Demelier <markand@malikania.fr>
date Sat, 12 Dec 2020 21:50:23 +0100
parents b1991ee4451d
children 939fe74cd80a
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.\"
.\" buf_reserve.3 -- simple string buffer for C
.\"
.\" Copyright (c) 2019-2020 David Demelier <markand@malikania.fr>
.\"
.\" Permission to use, copy, modify, and/or distribute this software for any
.\" purpose with or without fee is hereby granted, provided that the above
.\" copyright notice and this permission notice appear in all copies.
.\"
.\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
.\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
.\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
.\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
.\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
.\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
.\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
.\"
.Dd October 29, 2019-2020
.Dt BUF_RESERVE 3
.Os
.\" NAME
.Sh NAME
.Nm buf_reserve
.Nd allocate more storage for next operations
.\" SYNOPSIS
.Sh SYNOPSIS
.In buf.h
.Ft bool
.Fn buf_reserve "struct buf *b" "size_t desired"
.\" DESCRIPTION
.Sh DESCRIPTION
The
.Fn buf_reserve
function tries to increase the buffer's capacity specified by
.Fa b
to the amount of
.Fa desired .
.Pp
Once the new capacity is increased the next calls to any operation that would
append data to the buffer can avoid reallocating the memory.
This can be useful if you know in advance which storage space you need.
.Pp
If it was unable to acquire more memory, the buffer still contains the original
data and capacity remains unchanged.
In any case, the buffer length's remains unchanged and only capacity is
increased.
.\" RETURN VALUE
.Sh RETURN VALUE
The
.Fn buf_reserve
function returns false in case of error and
.Va errno
is set to indicate the error.
.\" ERRORS
.Sh ERRORS
.Bl -tag -width Er
.It Bq Er ENOMEM
Couldn't allocate more memory.
.El
.\" SEE ALSO
.Sh SEE ALSO
.Xr libbuf 3
.\" AUTHORS
.Sh AUTHORS
The
.Nm libbuf
library was written by
.An David Demelier <markand@malikania.fr>