NAME

       CURLSHOPT_LOCKFUNC - mutex lock callback

SYNOPSIS

       #include <curl/curl.h>

       void lockcb(CURL *handle, curl_lock_data data, curl_lock_access access,
                   void *userptr);

       CURLSHcode curl_share_setopt(CURLSH *share, CURLSHOPT_LOCKFUNC, lockcb);

DESCRIPTION

       Set a mutex lock callback for the share object, to allow it to get used by multiple threads concurrently.
       There's a corresponding CURLSHOPT_UNLOCKFUNC(3) callback called when the mutex is again relased.

       The  lockcb argument must be a pointer to a function matching the prototype shown above. The arguments to
       the callback are:

       handle is the currently active easy handle in use when the share object is intended to get used.

       The data argument tells what kind of data libcurl wants to lock. Make  sure  that  the  callback  uses  a
       different lock for each kind of data.

       access defines what access type libcurl wants, shared or single.

       userptr  is  the  private  pointer  you set with CURLSHOPT_USERDATA.  This pointer is not used by libcurl
       itself.

PROTOCOLS

       All

EXAMPLE

         CURLSHcode sh
         share = curl_share_init();
         sh = curl_share_setopt(share, CURLSHOPT_LOCKFUNC, mutex_lock);
         if(sh)
           printf("Error: %s\n", curl_share_strerror(sh));

AVAILABILITY

       Added in 7.10

RETURN VALUE

       CURLSHE_OK (zero) means that the option was set properly, non-zero means an error occurred. See  libcurl-
       errors(3) for the full list with descriptions.

SEE ALSO

       CURLSHOPT_UNLOCKFUNC(3), curl_share_setopt(3), curl_share_cleanup(3), curl_share_init(3)

libcurl 7.81.0                                  November 12, 2021                          CURLSHOPT_LOCKFUNC(3)