Server : ApacheSystem : Linux host44.registrar-servers.com 4.18.0-513.18.1.lve.2.el8.x86_64 #1 SMP Sat Mar 30 15:36:11 UTC 2024 x86_64 User : vapecompany ( 2719) PHP Version : 7.4.33 Disable Function : NONE Directory : /opt/alt/openssl/share/man/man3/ |
Upload File : |
.\" 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 "SSL_write 3"
.TH SSL_write 3 "2019-12-20" "1.0.2u" "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"
SSL_write \- write bytes to a TLS/SSL connection.
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
.Vb 1
\& #include <openssl/ssl.h>
\&
\& int SSL_write(SSL *ssl, const void *buf, int num);
.Ve
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
\&\fBSSL_write()\fR writes \fBnum\fR bytes from the buffer \fBbuf\fR into the specified
\&\fBssl\fR connection.
.SH "NOTES"
.IX Header "NOTES"
If necessary, \fBSSL_write()\fR will negotiate a \s-1TLS/SSL\s0 session, if
not already explicitly performed by \fBSSL_connect\fR\|(3) or
\&\fBSSL_accept\fR\|(3). If the
peer requests a re-negotiation, it will be performed transparently during
the \fBSSL_write()\fR operation. The behaviour of \fBSSL_write()\fR depends on the
underlying \s-1BIO.\s0
.PP
For the transparent negotiation to succeed, the \fBssl\fR must have been
initialized to client or server mode. This is being done by calling
\&\fBSSL_set_connect_state\fR\|(3) or \fBSSL_set_accept_state()\fR
before the first call to an \fBSSL_read\fR\|(3) or \fBSSL_write()\fR function.
.PP
If the underlying \s-1BIO\s0 is \fBblocking\fR, \fBSSL_write()\fR will only return, once the
write operation has been finished or an error occurred, except when a
renegotiation take place, in which case a \s-1SSL_ERROR_WANT_READ\s0 may occur.
This behaviour can be controlled with the \s-1SSL_MODE_AUTO_RETRY\s0 flag of the
\&\fBSSL_CTX_set_mode\fR\|(3) call.
.PP
If the underlying \s-1BIO\s0 is \fBnon-blocking\fR, \fBSSL_write()\fR will also return,
when the underlying \s-1BIO\s0 could not satisfy the needs of \fBSSL_write()\fR
to continue the operation. In this case a call to
\&\fBSSL_get_error\fR\|(3) with the
return value of \fBSSL_write()\fR will yield \fB\s-1SSL_ERROR_WANT_READ\s0\fR or
\&\fB\s-1SSL_ERROR_WANT_WRITE\s0\fR. As at any time a re-negotiation is possible, a
call to \fBSSL_write()\fR can also cause read operations! The calling process
then must repeat the call after taking appropriate action to satisfy the
needs of \fBSSL_write()\fR. The action depends on the underlying \s-1BIO.\s0 When using a
non-blocking socket, nothing is to be done, but \fBselect()\fR can be used to check
for the required condition. When using a buffering \s-1BIO,\s0 like a \s-1BIO\s0 pair, data
must be written into or retrieved out of the \s-1BIO\s0 before being able to continue.
.PP
\&\fBSSL_write()\fR will only return with success, when the complete contents
of \fBbuf\fR of length \fBnum\fR has been written. This default behaviour
can be changed with the \s-1SSL_MODE_ENABLE_PARTIAL_WRITE\s0 option of
\&\fBSSL_CTX_set_mode\fR\|(3). When this flag is set,
\&\fBSSL_write()\fR will also return with success, when a partial write has been
successfully completed. In this case the \fBSSL_write()\fR operation is considered
completed. The bytes are sent and a new \fBSSL_write()\fR operation with a new
buffer (with the already sent bytes removed) must be started.
A partial write is performed with the size of a message block, which is
16kB for SSLv3/TLSv1.
.SH "WARNING"
.IX Header "WARNING"
When an \fBSSL_write()\fR operation has to be repeated because of
\&\fB\s-1SSL_ERROR_WANT_READ\s0\fR or \fB\s-1SSL_ERROR_WANT_WRITE\s0\fR, it must be repeated
with the same arguments.
.PP
When calling \fBSSL_write()\fR with num=0 bytes to be sent the behaviour is
undefined.
.SH "RETURN VALUES"
.IX Header "RETURN VALUES"
The following return values can occur:
.IP "> 0" 4
.IX Item "> 0"
The write operation was successful, the return value is the number of
bytes actually written to the \s-1TLS/SSL\s0 connection.
.IP "<= 0" 4
.IX Item "<= 0"
The write operation was not successful, because either the connection was
closed, an error occurred or action must be taken by the calling process.
Call \fBSSL_get_error()\fR with the return value \fBret\fR to find out the reason.
.Sp
SSLv2 (deprecated) does not support a shutdown alert protocol, so it can
only be detected, whether the underlying connection was closed. It cannot
be checked, why the closure happened.
.Sp
Old documentation indicated a difference between 0 and \-1, and that \-1 was
retryable.
You should instead call \fBSSL_get_error()\fR to find out if it's retryable.
.SH "SEE ALSO"
.IX Header "SEE ALSO"
\&\fBSSL_get_error\fR\|(3), \fBSSL_read\fR\|(3),
\&\fBSSL_CTX_set_mode\fR\|(3), \fBSSL_CTX_new\fR\|(3),
\&\fBSSL_connect\fR\|(3), \fBSSL_accept\fR\|(3)
\&\fBSSL_set_connect_state\fR\|(3),
\&\fBssl\fR\|(3), \fBbio\fR\|(3)