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man pages section 3: Library Interfaces and Headers

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Updated: Thursday, June 13, 2019

curl_global_init (3)


curl_global_init - Global libcurl initialisation


#include <curl/curl.h>

CURLcode curl_global_init(long flags);


curl_global_init(3)             libcurl Manual             curl_global_init(3)

       curl_global_init - Global libcurl initialisation

       #include <curl/curl.h>

       CURLcode curl_global_init(long flags);

       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 mul-
       tiple calls have the same effect as one call.

       The flags option is a bit pattern that tells libcurl exactly what  fea-
       tures  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 run-
       ning.  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 ini-
       tialize 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.

              Initialize everything possible. This sets all known bits  except

              (This flag's presence or absence 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  ini-
              tialization of the SSL layer needs to be done by the application
              or at least outside of libcurl. The exact procedure  how  to  do
              SSL initialization depends on the TLS backend libcurl uses.

              Doing  TLS based transfers without having the TLS layer initial-
              ized may lead to unexpected behaviors.

              Initialize the Win32 socket libraries.

              The implication here is that if this bit is not  set,  the  ini-
              tialization  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.

              Initialise nothing extra. This sets no bit.

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

              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)

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

       See attributes(7) for descriptions of the following attributes:

       |Availability   | web/curl         |
       |Stability      | Uncommitted      |
       curl_global_init_mem(3), curl_global_cleanup(3), curl_global_sslset(3),
       curl_easy_init(3) libcurl(3)

       This     software     was    built    from    source    available    at
       https://github.com/oracle/solaris-userland.   The  original   community
       source    was    downloaded    from    https://github.com/curl/curl/ar-

       Further information about this software can be found on the open source
       community website at http://curl.haxx.se/.

libcurl 7.12                      11 May 2004              curl_global_init(3)