quickjs-tart

quickjs-based runtime for wallet-core logic
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curl_global_init.md (3913B)

      1 ---
      2 c: Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
      3 SPDX-License-Identifier: curl
      4 Title: curl_global_init
      5 Section: 3
      6 Source: libcurl
      7 See-also:
      8   - curl_easy_init (3)
      9   - curl_global_cleanup (3)
     10   - curl_global_init_mem (3)
     11   - curl_global_sslset (3)
     12   - curl_global_trace (3)
     13   - libcurl (3)
     14 Protocol:
     15   - All
     16 Added-in: 7.8
     17 ---
     18 
     19 # NAME
     20 
     21 curl_global_init - global libcurl initialization
     22 
     23 # SYNOPSIS
     24 
     25 ~~~c
     26 #include <curl/curl.h>
     27 
     28 CURLcode curl_global_init(long flags);
     29 ~~~
     30 
     31 # DESCRIPTION
     32 
     33 This function sets up the program environment that libcurl needs. Think of it
     34 as an extension of the library loader.
     35 
     36 This function must be called at least once within a program (a program is all
     37 the code that shares a memory space) before the program calls any other
     38 function in libcurl. The environment it sets up is constant for the life of
     39 the program and is the same for every program, so multiple calls have the same
     40 effect as one call.
     41 
     42 The flags option is a bit pattern that tells libcurl exactly what features to
     43 init, as described below. Set the desired bits by ORing the values together.
     44 In normal operation, you must specify CURL_GLOBAL_ALL. Do not use any other
     45 value unless you are familiar with it and mean to control internal operations
     46 of libcurl.
     47 
     48 This function is thread-safe on most platforms. Then curl_version_info(3) has
     49 the `threadsafe` feature set (added in 7.84.0).
     50 
     51 If this is not thread-safe (the bit mentioned above is not set), you must not
     52 call this function when any other thread in the program (i.e. a thread sharing
     53 the same memory) is running. This does not just mean no other thread that is
     54 using libcurl. Because curl_global_init(3) calls functions of other libraries
     55 that are similarly thread unsafe, it could conflict with any other thread that
     56 uses these other libraries.
     57 
     58 If you are initializing libcurl from a Windows DLL you should not initialize
     59 it from *DllMain* or a static initializer because Windows holds the loader
     60 lock during that time and it could cause a deadlock.
     61 
     62 See the description in libcurl(3) of global environment requirements for
     63 details of how to use this function.
     64 
     65 # FLAGS
     66 
     67 ## CURL_GLOBAL_ALL
     68 
     69 Initialize everything possible. This sets all known bits except
     70 **CURL_GLOBAL_ACK_EINTR**.
     71 
     72 ## CURL_GLOBAL_SSL
     73 
     74 (This flag's presence or absence serves no meaning since 7.57.0. The
     75 description below is for older libcurl versions.)
     76 
     77 Initialize SSL.
     78 
     79 The implication here is that if this bit is not set, the initialization of the
     80 SSL layer needs to be done by the application or at least outside of
     81 libcurl. The exact procedure how to do SSL initialization depends on the TLS
     82 backend libcurl uses.
     83 
     84 Doing TLS based transfers without having the TLS layer initialized may lead to
     85 unexpected behaviors.
     86 
     87 ## CURL_GLOBAL_WIN32
     88 
     89 Initialize the Win32 socket libraries.
     90 
     91 The implication here is that if this bit is not set, the initialization of
     92 Winsock has to be done by the application or you risk getting undefined
     93 behaviors. This option exists for when the initialization is handled outside
     94 of libcurl so there is no need for libcurl to do it again.
     95 
     96 ## CURL_GLOBAL_NOTHING
     97 
     98 Initialize nothing extra. This sets no bit.
     99 
    100 ## CURL_GLOBAL_DEFAULT
    101 
    102 A sensible default. It initializes both SSL and Win32. Right now, this equals
    103 the functionality of the **CURL_GLOBAL_ALL** mask.
    104 
    105 ## CURL_GLOBAL_ACK_EINTR
    106 
    107 This bit has no point since 7.69.0 but its behavior is instead the default.
    108 
    109 Before 7.69.0: when this flag is set, curl acknowledges EINTR condition when
    110 connecting or when waiting for data. Otherwise, curl waits until full timeout
    111 elapses. (Added in 7.30.0)
    112 
    113 # %PROTOCOLS%
    114 
    115 # EXAMPLE
    116 
    117 ~~~c
    118 int main(void)
    119 {
    120   curl_global_init(CURL_GLOBAL_DEFAULT);
    121 
    122   /* use libcurl, then before exiting... */
    123 
    124   curl_global_cleanup();
    125 }
    126 ~~~
    127 
    128 # %AVAILABILITY%
    129 
    130 # RETURN VALUE
    131 
    132 If this function returns non-zero, something went wrong and you cannot use the
    133 other curl functions.