zmq_ctx_get_ext(3)

NAME

zmq_ctx_get_ext - get extended context options

SYNOPSIS

int zmq_ctx_get_ext (void *context, int option_name, void *option_value, size_t *option_len);

DESCRIPTION

The zmq_ctx_get() function shall retrieve the value for the option specified by the option_name argument and store it in the buffer pointed to by the option_value argument. The option_len argument is the size in bytes of the buffer pointed to by option_value; upon successful completion zmq_ctx_get_ext() shall modify the option_len argument to indicate the actual size of the option value stored in the buffer.

The zmq_ctx_get_ext() function accepts all the option names accepted by zmq_ctx_get(). Options that make most sense to retrieve using zmq_ctx_get_ext() instead of zmq_ctx_get() are:

ZMQ_THREAD_NAME_PREFIX: Get name prefix for I/O threads

The ZMQ_THREAD_NAME_PREFIX argument gets the string prefix of each thread created for the internal context’s thread pool.

Option value type	character string
Option value unit	N/A
Default value	empty string

RETURN VALUE

The zmq_ctx_get_ext() 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 prefix on internal ZMQ thread names:.

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);

AUTHORS

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