22

✏️ Editing: BIO_tell.3

.\" Automatically generated by Pod::Man 4.11 (Pod::Simple 3.35)
.\"
.\" Standard preamble:
.\" ========================================================================
.de Sp \" Vertical space (when we can't use .PP)
.if t .sp .5v
.if n .sp
..
.de Vb \" Begin verbatim text
.ft CW
.nf
.ne \\$1
..
.de Ve \" End verbatim text
.ft R
.fi
..
.\" Set up some character translations and predefined strings.  \*(-- will
.\" give an unbreakable dash, \*(PI will give pi, \*(L" will give a left
.\" double quote, and \*(R" will give a right double quote.  \*(C+ will
.\" give a nicer C++.  Capital omega is used to do unbreakable dashes and
.\" therefore won't be available.  \*(C` and \*(C' expand to `' in nroff,
.\" nothing in troff, for use with C<>.
.tr \(*W-
.ds C+ C\v'-.1v'\h'-1p'\s-2+\h'-1p'+\s0\v'.1v'\h'-1p'
.ie n \{\
.    ds -- \(*W-
.    ds PI pi
.    if (\n(.H=4u)&(1m=24u) .ds -- \(*W\h'-12u'\(*W\h'-12u'-\" diablo 10 pitch
.    if (\n(.H=4u)&(1m=20u) .ds -- \(*W\h'-12u'\(*W\h'-8u'-\"  diablo 12 pitch
.    ds L" ""
.    ds R" ""
.    ds C` ""
.    ds C' ""
'br\}
.el\{\
.    ds -- \|\(em\|
.    ds PI \(*p
.    ds L" ``
.    ds R" ''
.    ds C`
.    ds C'
'br\}
.\"
.\" Escape single quotes in literal strings from groff's Unicode transform.
.ie \n(.g .ds Aq \(aq
.el       .ds Aq '
.\"
.\" If the F register is >0, we'll generate index entries on stderr for
.\" titles (.TH), headers (.SH), subsections (.SS), items (.Ip), and index
.\" entries marked with X<> in POD.  Of course, you'll have to process the
.\" output yourself in some meaningful fashion.
.\"
.\" Avoid warning from groff about undefined register 'F'.
.de IX
..
.nr rF 0
.if \n(.g .if rF .nr rF 1
.if (\n(rF:(\n(.g==0)) \{\
.    if \nF \{\
.        de IX
.        tm Index:\\$1\t\\n%\t"\\$2"
..
.        if !\nF==2 \{\
.            nr % 0
.            nr F 2
.        \}
.    \}
.\}
.rr rF
.\"
.\" Accent mark definitions (@(#)ms.acc 1.5 88/02/08 SMI; from UCB 4.2).
.\" Fear.  Run.  Save yourself.  No user-serviceable parts.
.    \" fudge factors for nroff and troff
.if n \{\
.    ds #H 0
.    ds #V .8m
.    ds #F .3m
.    ds #[ \f1
.    ds #] \fP
.\}
.if t \{\
.    ds #H ((1u-(\\\\n(.fu%2u))*.13m)
.    ds #V .6m
.    ds #F 0
.    ds #[ \&
.    ds #] \&
.\}
.    \" simple accents for nroff and troff
.if n \{\
.    ds ' \&
.    ds ` \&
.    ds ^ \&
.    ds , \&
.    ds ~ ~
.    ds /
.\}
.if t \{\
.    ds ' \\k:\h'-(\\n(.wu*8/10-\*(#H)'\'\h"|\\n:u"
.    ds ` \\k:\h'-(\\n(.wu*8/10-\*(#H)'\`\h'|\\n:u'
.    ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'^\h'|\\n:u'
.    ds , \\k:\h'-(\\n(.wu*8/10)',\h'|\\n:u'
.    ds ~ \\k:\h'-(\\n(.wu-\*(#H-.1m)'~\h'|\\n:u'
.    ds / \\k:\h'-(\\n(.wu*8/10-\*(#H)'\z\(sl\h'|\\n:u'
.\}
.    \" troff and (daisy-wheel) nroff accents
.ds : \\k:\h'-(\\n(.wu*8/10-\*(#H+.1m+\*(#F)'\v'-\*(#V'\z.\h'.2m+\*(#F'.\h'|\\n:u'\v'\*(#V'
.ds 8 \h'\*(#H'\(*b\h'-\*(#H'
.ds o \\k:\h'-(\\n(.wu+\w'\(de'u-\*(#H)/2u'\v'-.3n'\*(#[\z\(de\v'.3n'\h'|\\n:u'\*(#]
.ds d- \h'\*(#H'\(pd\h'-\w'~'u'\v'-.25m'\f2\(hy\fP\v'.25m'\h'-\*(#H'
.ds D- D\\k:\h'-\w'D'u'\v'-.11m'\z\(hy\v'.11m'\h'|\\n:u'
.ds th \*(#[\v'.3m'\s+1I\s-1\v'-.3m'\h'-(\w'I'u*2/3)'\s-1o\s+1\*(#]
.ds Th \*(#[\s+2I\s-2\h'-\w'I'u*3/5'\v'-.3m'o\v'.3m'\*(#]
.ds ae a\h'-(\w'a'u*4/10)'e
.ds Ae A\h'-(\w'A'u*4/10)'E
.    \" corrections for vroff
.if v .ds ~ \\k:\h'-(\\n(.wu*9/10-\*(#H)'\s-2\u~\d\s+2\h'|\\n:u'
.if v .ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'\v'-.4m'^\v'.4m'\h'|\\n:u'
.    \" for low resolution devices (crt and lpr)
.if \n(.H>23 .if \n(.V>19 \
\{\
.    ds : e
.    ds 8 ss
.    ds o a
.    ds d- d\h'-1'\(ga
.    ds D- D\h'-1'\(hy
.    ds th \o'bp'
.    ds Th \o'LP'
.    ds ae ae
.    ds Ae AE
.\}
.rm #[ #] #H #V #F C
.\" ========================================================================
.\"
.IX Title "BIO_CTRL 3"
.TH BIO_CTRL 3 "2023-09-11" "1.1.1w" "OpenSSL"
.\" For nroff, turn off justification.  Always turn off hyphenation; it makes
.\" way too many mistakes in technical documents.
.if n .ad l
.nh
.SH "NAME"
BIO_ctrl, BIO_callback_ctrl, BIO_ptr_ctrl, BIO_int_ctrl, BIO_reset, BIO_seek, BIO_tell, BIO_flush, BIO_eof, BIO_set_close, BIO_get_close, BIO_pending, BIO_wpending, BIO_ctrl_pending, BIO_ctrl_wpending, BIO_get_info_callback, BIO_set_info_callback, BIO_info_cb \&\- BIO control operations
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
.Vb 1
\& #include <openssl/bio.h>
\&
\& typedef int BIO_info_cb(BIO *b, int state, int res);
\&
\& long BIO_ctrl(BIO *bp, int cmd, long larg, void *parg);
\& long BIO_callback_ctrl(BIO *b, int cmd, BIO_info_cb *cb);
\& void *BIO_ptr_ctrl(BIO *bp, int cmd, long larg);
\& long BIO_int_ctrl(BIO *bp, int cmd, long larg, int iarg);
\&
\& int BIO_reset(BIO *b);
\& int BIO_seek(BIO *b, int ofs);
\& int BIO_tell(BIO *b);
\& int BIO_flush(BIO *b);
\& int BIO_eof(BIO *b);
\& int BIO_set_close(BIO *b, long flag);
\& int BIO_get_close(BIO *b);
\& int BIO_pending(BIO *b);
\& int BIO_wpending(BIO *b);
\& size_t BIO_ctrl_pending(BIO *b);
\& size_t BIO_ctrl_wpending(BIO *b);
\&
\& int BIO_get_info_callback(BIO *b, BIO_info_cb **cbp);
\& int BIO_set_info_callback(BIO *b, BIO_info_cb *cb);
.Ve
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
\&\fBBIO_ctrl()\fR, \fBBIO_callback_ctrl()\fR, \fBBIO_ptr_ctrl()\fR and \fBBIO_int_ctrl()\fR
are \s-1BIO\s0 \*(L"control\*(R" operations taking arguments of various types.
These functions are not normally called directly, various macros
are used instead. The standard macros are described below, macros
specific to a particular type of \s-1BIO\s0 are described in the specific
BIOs manual page as well as any special features of the standard
calls.
.PP
\&\fBBIO_reset()\fR typically resets a \s-1BIO\s0 to some initial state, in the case
of file related BIOs for example it rewinds the file pointer to the
start of the file.
.PP
\&\fBBIO_seek()\fR resets a file related \s-1BIO\s0's (that is file descriptor and
\&\s-1FILE\s0 BIOs) file position pointer to \fBofs\fR bytes from start of file.
.PP
\&\fBBIO_tell()\fR returns the current file position of a file related \s-1BIO.\s0
.PP
\&\fBBIO_flush()\fR normally writes out any internally buffered data, in some
cases it is used to signal \s-1EOF\s0 and that no more data will be written.
.PP
\&\fBBIO_eof()\fR returns 1 if the \s-1BIO\s0 has read \s-1EOF,\s0 the precise meaning of
\&\*(L"\s-1EOF\*(R"\s0 varies according to the \s-1BIO\s0 type.
.PP
\&\fBBIO_set_close()\fR sets the \s-1BIO\s0 \fBb\fR close flag to \fBflag\fR. \fBflag\fR can
take the value \s-1BIO_CLOSE\s0 or \s-1BIO_NOCLOSE.\s0 Typically \s-1BIO_CLOSE\s0 is used
in a source/sink \s-1BIO\s0 to indicate that the underlying I/O stream should
be closed when the \s-1BIO\s0 is freed.
.PP
\&\fBBIO_get_close()\fR returns the BIOs close flag.
.PP
\&\fBBIO_pending()\fR, \fBBIO_ctrl_pending()\fR, \fBBIO_wpending()\fR and \fBBIO_ctrl_wpending()\fR
return the number of pending characters in the BIOs read and write buffers.
Not all BIOs support these calls. \fBBIO_ctrl_pending()\fR and \fBBIO_ctrl_wpending()\fR
return a size_t type and are functions, \fBBIO_pending()\fR and \fBBIO_wpending()\fR are
macros which call \fBBIO_ctrl()\fR.
.SH "RETURN VALUES"
.IX Header "RETURN VALUES"
\&\fBBIO_reset()\fR normally returns 1 for success and 0 or \-1 for failure. File
BIOs are an exception, they return 0 for success and \-1 for failure.
.PP
\&\fBBIO_seek()\fR and \fBBIO_tell()\fR both return the current file position on success
and \-1 for failure, except file BIOs which for \fBBIO_seek()\fR always return 0
for success and \-1 for failure.
.PP
\&\fBBIO_flush()\fR returns 1 for success and 0 or \-1 for failure.
.PP
\&\fBBIO_eof()\fR returns 1 if \s-1EOF\s0 has been reached 0 otherwise.
.PP
\&\fBBIO_set_close()\fR always returns 1.
.PP
\&\fBBIO_get_close()\fR returns the close flag value: \s-1BIO_CLOSE\s0 or \s-1BIO_NOCLOSE.\s0
.PP
\&\fBBIO_pending()\fR, \fBBIO_ctrl_pending()\fR, \fBBIO_wpending()\fR and \fBBIO_ctrl_wpending()\fR
return the amount of pending data.
.SH "NOTES"
.IX Header "NOTES"
\&\fBBIO_flush()\fR, because it can write data may return 0 or \-1 indicating
that the call should be retried later in a similar manner to \fBBIO_write_ex()\fR.
The \fBBIO_should_retry()\fR call should be used and appropriate action taken
is the call fails.
.PP
The return values of \fBBIO_pending()\fR and \fBBIO_wpending()\fR may not reliably
determine the amount of pending data in all cases. For example in the
case of a file \s-1BIO\s0 some data may be available in the \s-1FILE\s0 structures
internal buffers but it is not possible to determine this in a
portably way. For other types of \s-1BIO\s0 they may not be supported.
.PP
Filter BIOs if they do not internally handle a particular \fBBIO_ctrl()\fR
operation usually pass the operation to the next \s-1BIO\s0 in the chain.
This often means there is no need to locate the required \s-1BIO\s0 for
a particular operation, it can be called on a chain and it will
be automatically passed to the relevant \s-1BIO.\s0 However, this can cause
unexpected results: for example no current filter BIOs implement
\&\fBBIO_seek()\fR, but this may still succeed if the chain ends in a \s-1FILE\s0
or file descriptor \s-1BIO.\s0
.PP
Source/sink BIOs return an 0 if they do not recognize the \fBBIO_ctrl()\fR
operation.
.SH "BUGS"
.IX Header "BUGS"
Some of the return values are ambiguous and care should be taken. In
particular a return value of 0 can be returned if an operation is not
supported, if an error occurred, if \s-1EOF\s0 has not been reached and in
the case of \fBBIO_seek()\fR on a file \s-1BIO\s0 for a successful operation.
.SH "COPYRIGHT"
.IX Header "COPYRIGHT"
Copyright 2000\-2022 The OpenSSL Project Authors. All Rights Reserved.
.PP
Licensed under the OpenSSL license (the \*(L"License\*(R").  You may not use
this file except in compliance with the License.  You can obtain a copy
in the file \s-1LICENSE\s0 in the source distribution or at
<https://www.openssl.org/source/license.html>.

MR SKB