Mercurial > hgrepos > Python2 > PyMuPDF

comparison mupdf-source/thirdparty/curl/docs/libcurl/curl_easy_pause.3 @ 2:b50eed0cc0ef upstream

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. The directory name has changed: no version number in the expanded directory now.
author Franz Glasner <fzglas.hg@dom66.de>
date Mon, 15 Sep 2025 11:43:07 +0200
parents
children
comparison
equal deleted inserted replaced
1:1d09e1dec1d9 2:b50eed0cc0ef
1 .\" **************************************************************************
2 .\" * _ _ ____ _
3 .\" * Project ___| | | | _ \| |
4 .\" * / __| | | | |_) | |
5 .\" * | (__| |_| | _ <| |___
6 .\" * \___|\___/|_| \_\_____|
7 .\" *
8 .\" * Copyright (C) 1998 - 2016, Daniel Stenberg, <daniel@haxx.se>, et al.
9 .\" *
10 .\" * This software is licensed as described in the file COPYING, which
11 .\" * you should have received as part of this distribution. The terms
12 .\" * are also available at https://curl.haxx.se/docs/copyright.html.
13 .\" *
14 .\" * You may opt to use, copy, modify, merge, publish, distribute and/or sell
15 .\" * copies of the Software, and permit persons to whom the Software is
16 .\" * furnished to do so, under the terms of the COPYING file.
17 .\" *
18 .\" * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
19 .\" * KIND, either express or implied.
20 .\" *
21 .\" **************************************************************************
22 .TH curl_easy_pause 3 "17 Dec 2007" "libcurl 7.18.0" "libcurl Manual"
23 .SH NAME
24 curl_easy_pause - pause and unpause a connection
25 .SH SYNOPSIS
26 .B #include <curl/curl.h>
27
28 .BI "CURLcode curl_easy_pause(CURL *"handle ", int "bitmask " );"
29
30 .SH DESCRIPTION
31 Using this function, you can explicitly mark a running connection to get
32 paused, and you can unpause a connection that was previously paused.
33
34 A connection can be paused by using this function or by letting the read or
35 the write callbacks return the proper magic return code
36 (\fICURL_READFUNC_PAUSE\fP and \fICURL_WRITEFUNC_PAUSE\fP). A write callback
37 that returns pause signals to the library that it couldn't take care of any
38 data at all, and that data will then be delivered again to the callback when
39 the writing is later unpaused.
40
41 While it may feel tempting, take care and notice that you cannot call this
42 function from another thread. To unpause, you may for example call it from the
43 progress callback (\fICURLOPT_PROGRESSFUNCTION(3)\fP), which gets called at
44 least once per second, even if the connection is paused.
45
46 When this function is called to unpause reading, the chance is high that you
47 will get your write callback called before this function returns.
48
49 The \fBhandle\fP argument is of course identifying the handle that operates on
50 the connection you want to pause or unpause.
51
52 The \fBbitmask\fP argument is a set of bits that sets the new state of the
53 connection. The following bits can be used:
54 .IP CURLPAUSE_RECV
55 Pause receiving data. There will be no data received on this connection until
56 this function is called again without this bit set. Thus, the write callback
57 (\fICURLOPT_WRITEFUNCTION(3)\fP) won't be called.
58 .IP CURLPAUSE_SEND
59 Pause sending data. There will be no data sent on this connection until this
60 function is called again without this bit set. Thus, the read callback
61 (\fICURLOPT_READFUNCTION(3)\fP) won't be called.
62 .IP CURLPAUSE_ALL
63 Convenience define that pauses both directions.
64 .IP CURLPAUSE_CONT
65 Convenience define that unpauses both directions.
66 .SH RETURN VALUE
67 CURLE_OK (zero) means that the option was set properly, and a non-zero return
68 code means something wrong occurred after the new state was set. See the
69 \fIlibcurl-errors(3)\fP man page for the full list with descriptions.
70 .SH LIMITATIONS
71 The pausing of transfers does not work with protocols that work without
72 network connectivity, like FILE://. Trying to pause such a transfer, in any
73 direction, will cause problems in the worst case or an error in the best case.
74 .SH AVAILABILITY
75 This function was added in libcurl 7.18.0. Before this version, there was no
76 explicit support for pausing transfers.
77 .SH "USAGE WITH THE MULTI-SOCKET INTERFACE"
78 Before libcurl 7.32.0, when a specific handle was unpaused with this function,
79 there was no particular forced rechecking or similar of the socket's state,
80 which made the continuation of the transfer get delayed until next
81 multi-socket call invoke or even longer. Alternatively, the user could
82 forcibly call for example \fIcurl_multi_socket_all(3)\fP - with a rather hefty
83 performance penalty.
84
85 Starting in libcurl 7.32.0, unpausing a transfer will schedule a timeout
86 trigger for that handle 1 millisecond into the future, so that a
87 curl_multi_socket_action( ... CURL_SOCKET_TIMEOUT) can be used immediately
88 afterwards to get the transfer going again as desired.
89 .SH "MEMORY USE"
90 When pausing a read by returning the magic return code from a write callback,
91 the read data is already in libcurl's internal buffers so it'll have to keep
92 it in an allocated buffer until the reading is again unpaused using this
93 function.
94
95 If the downloaded data is compressed and is asked to get uncompressed
96 automatically on download, libcurl will continue to uncompress the entire
97 downloaded chunk and it will cache the data uncompressed. This has the side-
98 effect that if you download something that is compressed a lot, it can result
99 in a very large data amount needing to be allocated to save the data during
100 the pause. This said, you should probably consider not using paused reading if
101 you allow libcurl to uncompress data automatically.
102 .SH "SEE ALSO"
103 .BR curl_easy_cleanup "(3), " curl_easy_reset "(3)"