Tribblix: manual page: CURLSHOPT

CURLSHOPT_LOCKFUNC(3) Introduction to Library Functions

NAME

CURLSHOPT_LOCKFUNC - mutex lock callback

SYNOPSIS

#include <curl/curl.h>

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

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 is a corresponding
CURLSHOPT_UNLOCKFUNC(3) callback called when the mutex is again
released.

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.

clientp is the private pointer you set with CURLSHOPT_USERDATA(3).
This pointer is not used by libcurl itself.

PROTOCOLS

This functionality affects all supported protocols

EXAMPLE

extern void mutex_lock(CURL *handle, curl_lock_data data,
curl_lock_access access, void *clientp);

int main(void)
{
CURLSHcode sh;
CURLSH *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 curl 7.10.3

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.