manpagez: man pages & more
man curl_global_init(3)
Home | html | info | man
curl_global_init(3)             libcurl Manual             curl_global_init(3)




NAME

       curl_global_init - Global libcurl initialisation


SYNOPSIS

       #include <curl/curl.h>

       curl_global_init(3) 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 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.


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  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 initializtion depends on the TLS backend libcurl uses.

              Doing  TLS based transfers without having the TLS layer initial-
              ized 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  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.

       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)



libcurl 7.57.0                 November 23, 2017           curl_global_init(3)

curl 7.57.0 - Generated Wed Nov 29 14:46:48 CST 2017
© manpagez.com 2000-2017
Individual documents may contain additional copyright information.