'\" t
.\"     Title: zmq_ctx_get
.\"    Author: [see the "AUTHORS" section]
.\" Generator: DocBook XSL Stylesheets vsnapshot <http://docbook.sf.net/>
.\"      Date: 01/17/2021
.\"    Manual: 0MQ Manual
.\"    Source: 0MQ 4.3.4
.\"  Language: English
.\"
.TH "ZMQ_CTX_GET" "3" "01/17/2021" "0MQ 4\&.3\&.4" "0MQ Manual"
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.SH "NAME"
zmq_ctx_get \- get context options
.SH "SYNOPSIS"
.sp
\fBint zmq_ctx_get (void \fR\fB\fI*context\fR\fR\fB, int \fR\fB\fIoption_name\fR\fR\fB);\fR
.SH "DESCRIPTION"
.sp
The \fIzmq_ctx_get()\fR function shall return the option specified by the \fIoption_name\fR argument\&.
.sp
The \fIzmq_ctx_get()\fR function accepts the following option names:
.SS "ZMQ_IO_THREADS: Get number of I/O threads"
.sp
The \fIZMQ_IO_THREADS\fR argument returns the size of the 0MQ thread pool for this context\&.
.SS "ZMQ_MAX_SOCKETS: Get maximum number of sockets"
.sp
The \fIZMQ_MAX_SOCKETS\fR argument returns the maximum number of sockets allowed for this context\&.
.SS "ZMQ_MAX_MSGSZ: Get maximum message size"
.sp
The \fIZMQ_MAX_MSGSZ\fR argument returns the maximum size of a message allowed for this context\&. Default value is INT_MAX\&.
.SS "ZMQ_ZERO_COPY_RECV: Get message decoding strategy"
.sp
The \fIZMQ_ZERO_COPY_RECV\fR argument return whether message decoder uses a zero copy strategy when receiving messages\&. Default value is 1\&. NOTE: in DRAFT state, not yet available in stable releases\&.
.SS "ZMQ_SOCKET_LIMIT: Get largest configurable number of sockets"
.sp
The \fIZMQ_SOCKET_LIMIT\fR argument returns the largest number of sockets that \fBzmq_ctx_set\fR(3) will accept\&.
.SS "ZMQ_IPV6: Set IPv6 option"
.sp
The \fIZMQ_IPV6\fR argument returns the IPv6 option for the context\&.
.SS "ZMQ_BLOCKY: Get blocky setting"
.sp
The \fIZMQ_BLOCKY\fR argument returns 1 if the context will block on terminate, zero if the "block forever on context termination" gambit was disabled by setting ZMQ_BLOCKY to false on all new contexts\&.
.SS "ZMQ_THREAD_SCHED_POLICY: Get scheduling policy for I/O threads"
.sp
The \fIZMQ_THREAD_SCHED_POLICY\fR argument returns the scheduling policy for internal context\(cqs thread pool\&.
.SS "ZMQ_THREAD_NAME_PREFIX: Get name prefix for I/O threads"
.sp
The \fIZMQ_THREAD_NAME_PREFIX\fR argument gets the numeric prefix of each thread created for the internal context\(cqs thread pool\&.
.SS "ZMQ_MSG_T_SIZE: Get the zmq_msg_t size at runtime"
.sp
The \fIZMQ_MSG_T_SIZE\fR argument returns the size of the zmq_msg_t structure at runtime, as defined in the include/zmq\&.h public header\&. This is useful for example for FFI bindings that can\(cqt simply do a sizeof()\&.
.SH "RETURN VALUE"
.sp
The \fIzmq_ctx_get()\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 limit on the number of sockets\fR. 
.sp
.if n \{\
.RS 4
.\}
.nf
void *context = zmq_ctx_new ();
zmq_ctx_set (context, ZMQ_MAX_SOCKETS, 256);
int max_sockets = zmq_ctx_get (context, ZMQ_MAX_SOCKETS);
assert (max_sockets == 256);
.fi
.if n \{\
.RE
.\}
.PP
\fBSwitching off the context deadlock gambit\fR. 
.sp
.if n \{\
.RS 4
.\}
.nf
zmq_ctx_set (ctx, ZMQ_BLOCKY, false);
.fi
.if n \{\
.RE
.\}
.sp
.SH "SEE ALSO"
.sp
\fBzmq_ctx_set\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[]\&.