zmq_ctx_get - Man Page
get context options
Synopsis
int zmq_ctx_get (void *context, int option_name);
Description
The zmq_ctx_get() function shall return the option specified by the option_name argument.
The zmq_ctx_get() function accepts the following option names:
ZMQ_IO_THREADS: Get number of I/O threads
The ZMQ_IO_THREADS argument returns the size of the 0MQ thread pool for this context.
ZMQ_MAX_SOCKETS: Get maximum number of sockets
The ZMQ_MAX_SOCKETS argument returns the maximum number of sockets allowed for this context.
ZMQ_MAX_MSGSZ: Get maximum message size
The ZMQ_MAX_MSGSZ argument returns the maximum size of a message allowed for this context. Default value is INT_MAX.
ZMQ_ZERO_COPY_RECV: Get message decoding strategy
The ZMQ_ZERO_COPY_RECV 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.
ZMQ_SOCKET_LIMIT: Get largest configurable number of sockets
The ZMQ_SOCKET_LIMIT argument returns the largest number of sockets that zmq_ctx_set(3) will accept.
ZMQ_IPV6: Set IPv6 option
The ZMQ_IPV6 argument returns the IPv6 option for the context.
ZMQ_BLOCKY: Get blocky setting
The ZMQ_BLOCKY 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.
ZMQ_THREAD_SCHED_POLICY: Get scheduling policy for I/O threads
The ZMQ_THREAD_SCHED_POLICY argument returns the scheduling policy for internal context’s thread pool.
ZMQ_THREAD_NAME_PREFIX: Get name prefix for I/O threads
The ZMQ_THREAD_NAME_PREFIX argument gets the numeric prefix of each thread created for the internal context’s thread pool.
ZMQ_MSG_T_SIZE: Get the zmq_msg_t size at runtime
The ZMQ_MSG_T_SIZE 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’t simply do a sizeof().
Return Value
The zmq_ctx_get() function returns a value of 0 or greater if successful. Otherwise it returns -1 and sets errno to one of the values defined below.
Errors
- EINVAL
The requested option option_name is unknown.
- EFAULT
The provided context is invalid.
Example
Setting a limit on the number of sockets.
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);
Switching off the context deadlock gambit.
zmq_ctx_set (ctx, ZMQ_BLOCKY, false);
See Also
Authors
This page was written by the 0MQ community. To make a change please read the 0MQ Contribution Policy at http://www.zeromq.org/docs:contributing.
Referenced By
zmq(7), zmq_ctx_new(3), zmq_ctx_set(3).