'\" t
.\"     Title: zmq_ctx_get_ext
.\"    Author: [see the "AUTHORS" section]
.\" Generator: DocBook XSL Stylesheets vsnapshot <http://docbook.sf.net/>
.\"      Date: 10/23/2023
.\"    Manual: 0MQ Manual
.\"    Source: 0MQ 4.3.5
.\"  Language: English
.\"
.TH "ZMQ_CTX_GET_EXT" "3" "10/23/2023" "0MQ 4\&.3\&.5" "0MQ Manual"
.\" -----------------------------------------------------------------
.\" * Define some portability stuff
.\" -----------------------------------------------------------------
.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
.\" http://bugs.debian.org/507673
.\" http://lists.gnu.org/archive/html/groff/2009-02/msg00013.html
.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
.ie \n(.g .ds Aq \(aq
.el       .ds Aq '
.\" -----------------------------------------------------------------
.\" * set default formatting
.\" -----------------------------------------------------------------
.\" disable hyphenation
.nh
.\" disable justification (adjust text to left margin only)
.ad l
.\" -----------------------------------------------------------------
.\" * MAIN CONTENT STARTS HERE *
.\" -----------------------------------------------------------------
.SH "NAME"
zmq_ctx_get_ext \- get extended context options
.SH "SYNOPSIS"
.sp
\fBint zmq_ctx_get_ext (void \fR\fB\fI*context\fR\fR\fB, int \fR\fB\fIoption_name\fR\fR\fB, void \fR\fB\fI*option_value\fR\fR\fB, size_t \fR\fB\fI*option_len\fR\fR\fB);\fR
.SH "DESCRIPTION"
.sp
The \fIzmq_ctx_get()\fR function shall retrieve the value for the option specified by the \fIoption_name\fR argument and store it in the buffer pointed to by the \fIoption_value\fR argument\&. The \fIoption_len\fR argument is the size in bytes of the buffer pointed to by \fIoption_value\fR; upon successful completion \fIzmq_ctx_get_ext()\fR shall modify the \fIoption_len\fR argument to indicate the actual size of the option value stored in the buffer\&.
.sp
The \fIzmq_ctx_get_ext()\fR function accepts all the option names accepted by \fIzmq_ctx_get()\fR\&. Options that make most sense to retrieve using \fIzmq_ctx_get_ext()\fR instead of \fIzmq_ctx_get()\fR are:
.SS "ZMQ_THREAD_NAME_PREFIX: Get name prefix for I/O threads"
.sp
The \fIZMQ_THREAD_NAME_PREFIX\fR argument gets the string prefix of each thread created for the internal context\(cqs thread pool\&.
.TS
tab(:);
lt lt
lt lt
lt lt.
T{
.sp
Option value type
T}:T{
.sp
character string
T}
T{
.sp
Option value unit
T}:T{
.sp
N/A
T}
T{
.sp
Default value
T}:T{
.sp
empty string
T}
.TE
.sp 1
.SH "RETURN VALUE"
.sp
The \fIzmq_ctx_get_ext()\fR function returns a value of 0 or greater if successful\&. Otherwise it returns \-1 and sets \fIerrno\fR to one of the values defined below\&.
.SH "ERRORS"
.PP
\fBEINVAL\fR
.RS 4
The requested option
\fIoption_name\fR
is unknown\&.
.RE
.PP
\fBEFAULT\fR
.RS 4
The provided
\fIcontext\fR
is invalid\&.
.RE
.SH "EXAMPLE"
.PP
\fBSetting a prefix on internal ZMQ thread names:\fR. 
.sp
.if n \{\
.RS 4
.\}
.nf
void *context = zmq_ctx_new ();
const char prefix[] = "MyApp";
size_t prefixLen = sizeof(prefix);
zmq_ctx_set (context, ZMQ_THREAD_NAME_PREFIX, &prefix, &prefixLen);

char buff[256];
size_t buffLen = sizeof(buff);
int rc = zmq_ctx_get (context, ZMQ_THREAD_NAME_PREFIX, &buff, &buffLen);
assert (rc == 0);
assert (buffLen == prefixLen);
.fi
.if n \{\
.RE
.\}
.sp
.SH "SEE ALSO"
.sp
\fBzmq_ctx_get\fR(3) \fBzmq\fR(7)
.SH "AUTHORS"
.sp
This page was written by the 0MQ community\&. To make a change please read the 0MQ Contribution Policy at \m[blue]\fBhttp://www\&.zeromq\&.org/docs:contributing\fR\m[]\&.