ZMQ_CTX_GET_EXT(3)

💖 ZMQ_CTX_GET_EXT(3) — straight from the 0MQ Manual 💖

Okay bestie, welcome to the page for zmq_ctx_get_ext, fresh out of the 0MQ Manual and ready to spill the extended-context-options tea ☕✨

✨ 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 🦋

So the manual literally says zmq_ctx_get() in this sentence — keeping it exactly as written, no edits: 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. Slay, that's the whole data-flow situation 💅

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. Periodt.

💅 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);

🌈 SEE ALSO 🌈

• zmq_ctx_get(3)
• zmq(7)

🫶 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.

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That's the whole vibe, bestie. This page is from 0MQ 4.3.5, dated 02/15/2026. Go get those extended context options — no cap, you've got this 💜✨