This function sets up the program environment that libcurl needs. Think of it
as an extension of the library loader.
This function must be called at least once within a program (a program is all
the code that shares a memory space) before the program calls any other
function in libcurl. The environment it sets up is constant for the life of
the program and is the same for every program, so multiple calls have the same
effect as one call.
The flags option is a bit pattern that tells libcurl exactly what features to
init, as described below. Set the desired bits by ORing the values together.
In normal operation, you must specify CURL_GLOBAL_ALL. Dont use any other
value unless you are familiar with it and mean to control internal operations of
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 doesnt just mean no other thread that is using libcurl. Because
curl_global_init(3) calls functions of other libraries that are
similarly thread unsafe, it could conflict with any other thread that uses
these other libraries.
If you are initializing libcurl from a Windows DLL you should not initialize it
from DllMain or a static initializer because Windows holds the loader lock
during that time and it could cause a deadlock.
See the description in libcurl(3) of global environment requirements for
details of how to use this function.