gnurl_multi_info_read(3)

💖 NAME 💖

curl_multi_info_read — read multi stack informationals. Also hi bestie, this is the gnurl_multi_info_read(3) page from the libgnurl Manual ✨

🦋 SYNOPSIS 🦋

#include <gnurl/curl.h>

CURLMsg *curl_multi_info_read( CURLM *multi_handle,
                               int *msgs_in_queue);

🌸 DESCRIPTION 🌸

Okay so the vibe is: you ask the multi handle if there are any messages/informationals from the individual transfers 👀 Messages may include informationals such as an error code from the transfer or just the fact that a transfer is completed. And fr fr, more details on these should be written down as well 📝

Repeated calls to this function will return a new struct each time, until a NULL is returned as a signal that there is no more to get at this point. The integer pointed to with msgs_in_queue will contain the number of remaining messages after this function was called. Slay, that's your queue count 💅

When you fetch a message using this function, it is removed from the internal queue so calling this function again will not return the same message again. It will instead return new messages at each new invoke until the queue is emptied. No reruns, bestie 🚫🔁

⚠️ WARNING: The data the returned pointer points to will not survive calling curl_multi_cleanup(3), curl_multi_remove_handle(3) or curl_easy_cleanup(3). Like, do not hold onto that pointer after cleanup — it's giving expired vibe check 💀

The 'CURLMsg' struct is very simple and only contains very basic information. If more involved information is wanted, the particular "easy handle" is present in that struct and can be used in subsequent regular curl_easy_getinfo(3) calls (or similar):

struct CURLMsg {
  CURLMSG msg;       /* what this message means */
  CURL *easy_handle; /* the handle it concerns */
  union {
    void *whatever;    /* message-specific data */
    CURLcode result;   /* return code for transfer */
  } data;
};

When msg is CURLMSG_DONE, the message identifies a transfer that is done, and then result contains the return code for the easy handle that just completed. Iconic completion moment 🎀

At this point, there are no other msg types defined. That's the whole menu, bestie 🍓

🔥 EXAMPLE 🔥

struct CURLMsg *m;

/* call curl_multi_perform or curl_multi_socket_action first, then loop
   through and check if there are any transfers that have completed */

do {
  int msgq = 0;
  m = curl_multi_info_read(multi_handle, &msgq);
  if(m && (m->msg == CURLMSG_DONE)) {
    CURL *e = m->easy_handle;
    transfers--;
    curl_multi_remove_handle(multi_handle, e);
    curl_easy_cleanup(e);
  }
} while(m);

✨ RETURN VALUE ✨

A pointer to a filled-in struct, or NULL if it failed or ran out of structs. It also writes the number of messages left in the queue (after this read) in the integer the second argument points to. So yeah, pointer plus queue-count tea ☕

🫶 SEE ALSO 🫶

• curl_multi_cleanup(3)
• curl_multi_init(3)
• curl_multi_perform(3)

mwah 💋 this page is the gnurl_multi_info_read(3) situation from libcurl 7.10.3, dated 18 Dec 2004 — go be the main character of your event loop, bestie 🌈👑