78 lines
1.8 KiB
Markdown
78 lines
1.8 KiB
Markdown
---
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c: Copyright (C) Daniel Stenberg, <daniel.se>, et al.
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SPDX-License-Identifier: curl
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Title: CURLSHOPT_LOCKFUNC
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Section: 3
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Source: libcurl
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See-also:
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- CURLSHOPT_UNLOCKFUNC (3)
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- curl_share_cleanup (3)
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- curl_share_init (3)
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- curl_share_setopt (3)
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---
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# NAME
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CURLSHOPT_LOCKFUNC - mutex lock callback
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# SYNOPSIS
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~~~c
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#include <curl/curl.h>
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void lockcb(CURL *handle, curl_lock_data data, curl_lock_access access,
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void *clientp);
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CURLSHcode curl_share_setopt(CURLSH *share, CURLSHOPT_LOCKFUNC, lockcb);
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~~~
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# DESCRIPTION
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Set a mutex lock callback for the share object, to allow it to get used by
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multiple threads concurrently. There is a corresponding
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CURLSHOPT_UNLOCKFUNC(3) callback called when the mutex is again released.
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The *lockcb* argument must be a pointer to a function matching the
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prototype shown above. The arguments to the callback are:
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*handle* is the currently active easy handle in use when the share object
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is intended to get used.
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The *data* argument tells what kind of data libcurl wants to lock. Make
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sure that the callback uses a different lock for each kind of data.
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*access* defines what access type libcurl wants, shared or single.
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*clientp* is the private pointer you set with CURLSHOPT_USERDATA(3).
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This pointer is not used by libcurl itself.
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# PROTOCOLS
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All
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# EXAMPLE
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~~~c
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extern void mutex_lock(CURL *handle, curl_lock_data data,
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curl_lock_access access, void *clientp);
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int main(void)
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{
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CURLSHcode sh;
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CURLSH *share = curl_share_init();
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sh = curl_share_setopt(share, CURLSHOPT_LOCKFUNC, mutex_lock);
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if(sh)
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printf("Error: %s\n", curl_share_strerror(sh));
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}
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~~~
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# AVAILABILITY
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Added in 7.10
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# RETURN VALUE
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CURLSHE_OK (zero) means that the option was set properly, non-zero means an
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error occurred. See libcurl-errors(3) for the full list with
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descriptions.
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