curl_global_cleanup man page
curl_global_cleanup — global libcurl cleanup
This function releases resources acquired by curl_global_init(3).
You should call curl_global_cleanup(3) once for each call you make to curl_global_init(3), after you are done using libcurl.
This function is not thread safe. You must not call it when any other thread in the program (i.e. a thread sharing the same memory) is running. This doesn't just mean no other thread that is using libcurl. Because curl_global_cleanup(3) calls functions of other libraries that are similarly thread unsafe, it could conflict with any other thread that uses these other libraries.
See the description in libcurl(3) of global environment requirements for details of how to use this function.
curl_global_cleanup(3) does not block waiting for any libcurl-created threads to terminate (such as threads used for name resolving). If a module containing libcurl is dynamically unloaded while libcurl-created threads are still running then your program may crash or other corruption may occur. We recommend you do not run libcurl from any module that may be unloaded dynamically. This behavior may be addressed in the future.
curl_global_init(3), libcurl(3), libcurl-thread(3),
curl_global_init(3), curl_global_init_mem(3), libcurl(3), libcurl-tutorial(3).