NAME

       curl_global_init - Global libcurl initialisation

SYNOPSIS

       #include <curl/curl.h>

       CURLcode curl_global_init(long flags);

DESCRIPTION

       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.   Don't use any other value unless you are familiar with it and mean to control internal
       operations of 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_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.

FLAGS

       CURL_GLOBAL_ALL
              Initialize everything possible. This sets all known bits except CURL_GLOBAL_ACK_EINTR.

       CURL_GLOBAL_SSL
              (This  flag's  presence  or  absense  serves no meaning since 7.57.0. The description below is for
              older libcurl versions.)

              Initialize SSL.

              The implication here is that if this bit is not set, the initialization of the SSL layer needs  to
              be  done  by  the  application  or  at least outside of libcurl. The exact procedure how to do SSL
              initializtion depends on the TLS backend libcurl uses.

              Doing TLS based transfers without  having  the  TLS  layer  initialized  may  lead  to  unexpected
              behaviors.

       CURL_GLOBAL_WIN32
              Initialize the Win32 socket libraries.

              The  implication here is that if this bit is not set, the initialization of winsock has to be done
              by the application or you risk getting undefined  behaviors.  This  option  exists  for  when  the
              initialization is handled outside of libcurl so there's no need for libcurl to do it again.

       CURL_GLOBAL_NOTHING
              Initialise nothing extra. This sets no bit.

       CURL_GLOBAL_DEFAULT
              A  sensible  default. It will init both SSL and Win32. Right now, this equals the functionality of
              the CURL_GLOBAL_ALL mask.

       CURL_GLOBAL_ACK_EINTR
              When this flag is set, curl will acknowledge EINTR condition when connecting or when  waiting  for
              data.  Otherwise, curl waits until full timeout elapses. (Added in 7.30.0)

RETURN VALUE

       If this function returns non-zero, something went wrong and you cannot use the other curl functions.

SEE ALSO

       curl_global_init_mem(3), curl_global_cleanup(3), curl_global_sslset(3), curl_easy_init(3) libcurl(3)