This is an interface to the libcurl library.
Converted to D from curl headers by htod and
cleaned up by Jonas Drewsen (jdrewsen)
Copyright (C) 1998 - 2010, Daniel Stenberg, <firstname.lastname@example.org>, et al.
This software is licensed as described in the file COPYING, which you should have received as part of this distribution. The terms are also available at http://curl.haxx.se/docs/copyright.html.
You may opt to use, copy, modify, merge, publish, distribute and/or sell copies of the Software, and permit persons to whom the Software is furnished to do so, under the terms of the COPYING file.
This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or implied.
This is the global package copyright
This is the version number of the libcurl package from which this header file origins:
The numeric version number is also available "in parts" by using these constants
This is the numeric version of the libcurl version number, meant for easier parsing and comparions by programs. The LIBCURL_VERSION_NUM define will always follow this syntax:
Where XX, YY and ZZ are the main version, release and patch numbers in hexadecimal (using 8 bits each). All three numbers are always represented using two digits. 1.2 would appear as "0x010200" while version 9.11.7 appears as "0x090b07".
This 6-digit (24 bits) hexadecimal number does not show pre-release number, and it is always a greater number in a more recent release. It makes comparisons with greater than and less than work.
This is the date and time when the full source package was created. The timestamp is not stored in git, as the timestamp is properly set in the tarballs by the maketgz script.
The format of the date should follow this template:
"Mon Feb 12 11:35:33 UTC 2007"
Data type definition of curl_off_t. jdrewsen - Always 64bit signed and that is what long is in D. Comment below is from curlbuild.h:
For any given platform/compiler curl_off_t must be typedef'ed to a 64-bit wide signed integral data type. The width of this data type must remain constant and independent of any possible large file support settings.
As an exception to the above, curl_off_t shall be typedef'ed to a 32-bit wide signed integral data type if there is no 64-bit type.
jdrewsen - Get socket alias from std.socket
jdrewsen - Would like to get socket error constant from std.socket by it is private atm.
next entry in the list
pointer to allocated name
length of name length
pointer to allocated data contents
length of contents field
pointer to allocated buffer contents
length of buffer field
list of extra headers for this form
if one field name has more than one file, this link should link to following files
as defined below
The file name to show. If not set, the actual file name will be used (if this is a file part)
custom pointer used for HTTPPOST_CALLBACK posts
specified content is a file name
specified content is a file name
name is only stored pointer do not free in formfree
contents is only stored pointer do not free in formfree
upload file from buffer
upload file from pointer contents
upload file contents by using the regular read callback to get the data and pass the given pointer as custom pointer
Tests have proven that 20K is a very bad buffer size for uploads on Windows, while 16K for some odd reason performed a lot better. We do the ifndef check to allow this value to easier be changed at build time for those who feel adventurous. The practical minimum is about 400 bytes since libcurl uses a buffer of this size as a scratch area (unrelated to network send operations).
The only reason to have a max limit for this is to avoid the risk of a bad server feeding libcurl with a never-ending header that will cause reallocs infinitely
This is a magic return code for the write callback that, when returned, will signal libcurl to pause receiving on the current transfer.
enumeration of file types
Content of this structure depends on information which is known and is achievable (e.g. by FTP LIST parsing). Please see the url_easy_setopt(3) man page for callbacks returning this structure -- some fields are mandatory, some others are optional. The FLAG field has special meaning. If some of these fields is not NULL, it is a pointer to b_data.
Content of this structure depends on information which is known and is achievable (e.g. by FTP LIST parsing). Please see the url_easy_setopt(3) man page for callbacks returning this structure -- some fields are mandatory, some others are optional. The FLAG field has special meaning.
return codes for CURLOPT_CHUNK_BGN_FUNCTION
if splitting of data transfer is enabled, this callback is called before download of an individual chunk started. Note that parameter "remains" works only for FTP wildcard downloading (for now), otherwise is not used
If splitting of data transfer is enabled this callback is called after download of an individual chunk finished. Note! After this callback was set then it have to be called FOR ALL chunks. Even if downloading of this chunk was skipped in CHUNK_BGN_FUNC. This is the reason why we don't need "transfer_info" parameter in this callback and we are not interested in "remains" parameter too.
callback type for wildcard downloading pattern matching. If the string matches the pattern, return CURL_FNMATCHFUNC_MATCH value, etc.
These are the return codes for the seek callbacks
addrlen was a socklen_t type before 7.18.0 but it turned really ugly and painful on the systems that lack this type
The following typedef's are signatures of malloc, free, realloc, strdup and calloc respectively. Function pointers of these types can be passed to the curl_global_init_mem() function to set user defined memory management callback routines.
the kind of data that is passed to information_callback
All possible error codes from all sorts of curl functions. Future versions may return other values, stay prepared.
Always add new return codes last. Never *EVER* remove any. The return codes must remain the same!
4 - NOT USED
9 a service was denied by the server due to lack of access - when login fails this is not returned.
10 - NOT USED
12 - NOT USED
16 - NOT USED
20 - NOT USED
21 - quote command failure
24 - NOT USED
25 - failed upload "command"
26 - couldn't open/read from file
29 - NOT USED
30 - FTP PORT operation failed
31 - the REST command failed
32 - NOT USED
33 - RANGE "command" didn't work
35 - wrong when connecting with SSL
36 - couldn't resume download
40 - NOT USED
44 - NOT USED
45 - CURLOPT_INTERFACE failed
46 - NOT USED
47 - catch endless re-direct loops
48 - User specified an unknown option
49 - Malformed telnet option
50 - NOT USED
51 - peer's certificate or fingerprint wasn't verified fine
52 - when this is a specific error
53 - SSL crypto engine not found
54 - can not set SSL crypto engine as default
55 - failed sending network data
56 - failure in receiving network data
57 - NOT IN USE
58 - problem with the local certificate
59 - couldn't use specified cipher
60 - problem with the CA cert (path?)
61 - Unrecognized transfer encoding
62 - Invalid LDAP URL
63 - Maximum file size exceeded
64 - Requested FTP SSL level failed
65 - Sending the data requires a rewind that failed
66 - failed to initialise ENGINE
67 - user, password or similar was not accepted and we failed to login
68 - file not found on server
69 - permission problem on server
70 - out of disk space on server
71 - Illegal TFTP operation
72 - Unknown transfer ID
73 - File already exists
74 - No such user
75 - conversion failed
76 - caller must register conversion callbacks using curl_easy_setopt options CURLOPT_CONV_FROM_NETWORK_FUNCTION, CURLOPT_CONV_TO_NETWORK_FUNCTION, and CURLOPT_CONV_FROM_UTF8_FUNCTION
77 - could not load CACERT file, missing or wrong format
78 - remote file not found
79 - error from the SSH layer, somewhat generic so the error message will be of interest when this has happened
80 - Failed to shut down the SSL connection
81 - socket is not ready for send/recv, wait till it's ready and try again (Added in 7.18.2)
82 - could not load CRL file, missing or wrong format (Added in 7.19.0)
83 - Issuer check failed. (Added in 7.19.0)
84 - a PRET command failed
85 - mismatch of RTSP CSeq numbers
86 - mismatch of RTSP Session Identifiers
87 - unable to parse FTP file list
88 - chunk callback reported error
This prototype applies to all conversion callbacks
actually an OpenSSL SSL_CTX
added in 7.10, new in 7.19.4 default is to use CONNECT HTTP/1.1
added in 7.19.4, force to use CONNECT HTTP/1.0
support added in 7.15.2, enum existed already in 7.10
added in 7.10
added in 7.18.0
Use the SOCKS5 protocol but pass along the host name rather than the IP address. added in 7.18.0
points to a zero-terminated string encoded with base64 if len is zero, otherwise to the "raw" data
this is the set of return values expected from the curl_sshkeycallback callback
this is the set of status codes pass in to the callback
parameter for the CURLOPT_USE_SSL option
parameter for the CURLOPT_FTP_SSL_CCC option
parameter for the CURLOPT_FTPSSLAUTH option
parameter for the CURLOPT_FTP_CREATE_MISSING_DIRS option
parameter for the CURLOPT_FTP_FILEMETHOD option
CURLPROTO_ defines are for the CURLOPT_*PROTOCOLS options
long may be 32 or 64 bits, but we should never depend on anything else but 32
name is uppercase CURLOPT_
This is the FILE * or void * the regular output should be written to.
The full URL to get/put
Port number to connect to, if other than default.
Name of proxy to use.
"name:password" to use when fetching.
"name:password" to use with proxy.
Range to get, specified as an ASCII string.
not used Specified file stream to upload from (use as input):
Buffer to receive error messages in, must be at least CURL_ERROR_SIZE bytes big. If this is not used, error messages go to stderr instead:
Function that will be called to store the output (instead of fwrite). The parameters will use fwrite() syntax, make sure to follow them.
Function that will be called to read the input (instead of fread). The parameters will use fread() syntax, make sure to follow them.
Time-out the read operation after this amount of seconds
If the CURLOPT_INFILE is used, this can be used to inform libcurl about how large the file being sent really is. That allows better error checking and better verifies that the upload was successful. -1 means unknown size.
For large file support, there is also a LARGE version of the key which takes an off_t type, allowing platforms with larger off_t sizes to handle larger files. See below for INFILESIZE_LARGE.
POST static input fields.
Set the referrer page (needed by some CGIs)
Set the FTP PORT string (interface name, named or numerical IP address) Use i.e '-' to use default address.
Set the User-Agent string (examined by some CGIs)
If the download receives less than "low speed limit" bytes/second during "low speed time" seconds, the operations is aborted. You could i.e if you have a pretty high speed connection, abort if it is less than 2000 bytes/sec during 20 seconds. Set the "low speed limit"
Set the "low speed time"
Set the continuation offset.
Note there is also a LARGE version of this key which uses off_t types, allowing for large file offsets on platforms which use larger-than-32-bit off_t's. Look below for RESUME_FROM_LARGE.
Set cookie in request:
This points to a linked list of headers, struct curl_slist kind
This points to a linked list of post entries, struct curl_httppost
name of the file keeping your private SSL-certificate
password for the SSL or SSH private key
send TYPE parameter?
send linked-list of QUOTE commands
send FILE * or void * to store headers to, if you use a callback it is simply passed to the callback unmodified
point to a file to read the initial cookies from, also enables "cookie awareness"
What version to specifically try to use. See CURL_SSLVERSION defines below.
What kind of HTTP time condition to use, see defines
Time to use with the above condition. Specified in number of seconds since 1 Jan 1970
35 = OBSOLETE Custom request, for customizing the get command like
HTTP request, for odd commands like DELETE, TRACE and others
38 is not used send linked-list of post-transfer QUOTE commands
Pass a pointer to string of the output using full variable-replacement as described elsewhere.
talk a lot
throw the header out too
shut off the progress meter
use HEAD to get http document
no output on http error codes >= 300
this is an upload
HTTP POST method
return bare names when listing directories
Append instead of overwrite on upload!
Specify whether to read the user+password from the . netrc or the URL. This must be one of the CURL_NETRC_* enums below.
use Location: Luke!
transfer data in text/ASCII format
55 = OBSOLETE Function that will be called instead of the internal progress display function. This function should be defined as the curl_progress_callback prototype defines.
Data passed to the progress callback
We want the referrer field set automatically when following locations
Port of the proxy, can be set in the proxy string as well with: "[host]:[port]"
size of the POST input data, if strlen() is not good to use
tunnel non-http operations through a HTTP proxy
Set the interface string to use as outgoing network interface
Set the krb4/5 security level, this also enables krb4/5 awareness. This is a string, 'clear', 'safe', 'confidential' or 'private'. If the string is set but doesn't match one of these, 'private' will be used.
Set if we should verify the peer in ssl handshake, set 1 to verify.
The CApath or CAfile used to validate the peer certificate this option is used only if SSL_VERIFYPEER is true
66 = OBSOLETE 67 = OBSOLETE Maximum number of http redirects to follow
Pass a long set to 1 to get the date of the requested document (if possible)! Pass a zero to shut it off.
This points to a linked list of telnet options
Max amount of cached alive connections
What policy to use when closing connections when the cache is filled up
73 = OBSOLETE Set to explicitly use a new connection for the upcoming transfer. Do not use this unless you're absolutely sure of this, as it makes the operation slower and is less friendly for the network.
Set to explicitly forbid the upcoming transfer's connection to be re-used when done. Do not use this unless you're absolutely sure of this, as it makes the operation slower and is less friendly for the network.
Set to a file name that contains random data for libcurl to use to seed the random engine when doing SSL connects.
Set to the Entropy Gathering Daemon socket pathname
Time-out connect operations after this amount of seconds, if connects are OK within this time, then fine... This only aborts the connect phase. [Only works on unix-style/SIGALRM operating systems]
Function that will be called to store headers (instead of fwrite). The parameters will use fwrite() syntax, make sure to follow them.
Set this to force the HTTP request to get back to GET. Only really usable if POST, PUT or a custom request have been used first.
Set if we should verify the Common name from the peer certificate in ssl handshake, set 1 to check existence, 2 to ensure that it matches the provided hostname.
Specify which file name to write all known cookies in after completed operation. Set file name to "-" (dash) to make it go to stdout.
Specify which SSL ciphers to use
Specify which HTTP version to use! This must be set to one of the CURL_HTTP_VERSION* enums set below.
Specifically switch on or off the FTP engine's use of the EPSV command. By default, that one will always be attempted before the more traditional PASV command.
type of the file keeping your SSL-certificate ("DER", "PEM", "ENG")
name of the file keeping your private SSL-key
type of the file keeping your private SSL-key ("DER", "PEM", "ENG")
crypto engine for the SSL-sub system
set the crypto engine for the SSL-sub system as default the param has no meaning...
Non-zero value means to use the global dns cache
DNS cache timeout
send linked-list of pre-transfer QUOTE commands
set the debug function
set the data for the debug function
mark this as start of a cookie session
The CApath directory used to validate the peer certificate this option is used only if SSL_VERIFYPEER is true
Instruct libcurl to use a smaller receive buffer
Instruct libcurl to not use any signal/alarm handlers, even when using timeouts. This option is useful for multi-threaded applications. See libcurl-the-guide for more background information.
Provide a CURLShare for mutexing non-ts data
indicates type of proxy. accepted values are CURLPROXY_HTTP (default), CURLPROXY_SOCKS4, CURLPROXY_SOCKS4A and CURLPROXY_SOCKS5.
Set the Accept-Encoding string. Use this to tell a server you would like the response to be compressed.
Set pointer to private data
Set aliases for HTTP 200 in the HTTP Response header
Continue to send authentication (user+password) when following locations, even when hostname changed. This can potentially send off the name and password to whatever host the server decides.
Specifically switch on or off the FTP engine's use of the EPRT command ( it also disables the LPRT attempt). By default, those ones will always be attempted before the good old traditional PORT command.
Set this to a bitmask value to enable the particular authentications methods you like. Use this in combination with CURLOPT_USERPWD. Note that setting multiple bits may cause extra network round-trips.
Set the ssl context callback function, currently only for OpenSSL ssl_ctx in second argument. The function must be matching the curl_ssl_ctx_callback proto.
Set the userdata for the ssl context callback function's third argument
FTP Option that causes missing dirs to be created on the remote server. In 7.19.4 we introduced the convenience enums for this option using the CURLFTP_CREATE_DIR prefix.
Set this to a bitmask value to enable the particular authentications methods you like. Use this in combination with CURLOPT_PROXYUSERPWD. Note that setting multiple bits may cause extra network round-trips.
FTP option that changes the timeout, in seconds, associated with getting a response. This is different from transfer timeout time and essentially places a demand on the FTP server to acknowledge commands in a timely manner.
Set this option to one of the CURL_IPRESOLVE_* defines (see below) to tell libcurl to resolve names to those IP versions only. This only has affect on systems with support for more than one, i.e IPv4 and_ IPv6.
Set this option to limit the size of a file that will be downloaded from an HTTP or FTP server.
Note there is also LARGE version which adds large file support for platforms which have larger off_t sizes. See MAXFILESIZE_LARGE below.
See the comment for INFILESIZE above, but in short, specifies the size of the file being uploaded. -1 means unknown.
Sets the continuation offset. There is also a LONG version of this; look above for RESUME_FROM.
Sets the maximum size of data that will be downloaded from an HTTP or FTP server. See MAXFILESIZE above for the LONG version.
Set this option to the file name of your .netrc file you want libcurl to parse (using the CURLOPT_NETRC option). If not set, libcurl will do a poor attempt to find the user's home directory and check for a .netrc file in there.
Enable SSL/TLS for FTP, pick one of: CURLFTPSSL_TRY - try using SSL, proceed anyway otherwise CURLFTPSSL_CONTROL - SSL for the control connection or fail CURLFTPSSL_ALL - SSL for all communication or fail
The LARGE version of the standard POSTFIELDSIZE option
Enable/disable the TCP Nagle algorithm
122 OBSOLETE, used in 7.12.3. Gone in 7.13.0 123 OBSOLETE. Gone in 7.16.0 124 OBSOLETE, used in 7.12.3. Gone in 7.13.0 125 OBSOLETE, used in 7.12.3. Gone in 7.13.0 126 OBSOLETE, used in 7.12.3. Gone in 7.13.0 127 OBSOLETE. Gone in 7.16.0 128 OBSOLETE. Gone in 7.16.0 When FTP over SSL/TLS is selected (with CURLOPT_USE_SSL), this option can be used to change libcurl's default action which is to first try "AUTH SSL" and then "AUTH TLS" in this order, and proceed when a OK response has been received.
Available parameters are: CURLFTPAUTH_DEFAULT - let libcurl decide CURLFTPAUTH_SSL - try "AUTH SSL" first, then TLS CURLFTPAUTH_TLS - try "AUTH TLS" first, then SSL
132 OBSOLETE. Gone in 7.16.0 133 OBSOLETE. Gone in 7.16.0 zero terminated string for pass on to the FTP server when asked for "account" info
feed cookies into cookie engine
Set to non-zero to skip the IP address received in a 227 PASV FTP server response. Typically used for FTP-SSL purposes but is not restricted to that. libcurl will then instead use the same IP address it used for the control connection.
Select "file method" to use when doing FTP, see the curl_ftpmethod above.
Local port number to bind the socket to
Number of ports to try, including the first one set with LOCALPORT. Thus, setting it to 1 will make no additional attempts but the first.
no transfer, set up connection and let application use the socket by extracting it with CURLINFO_LASTSOCKET
Function that will be called to convert from the network encoding (instead of using the iconv calls in libcurl)
Function that will be called to convert to the network encoding (instead of using the iconv calls in libcurl)
Function that will be called to convert from UTF8 (instead of using the iconv calls in libcurl) Note that this is used only for SSL certificate processing
if the connection proceeds too quickly then need to slow it down limit-rate: maximum number of bytes per second to send or receive
Pointer to command string to send if USER/PASS fails.
callback function for setting socket options
set to 0 to disable session ID re-use for this transfer, default is enabled (== 1)
allowed SSH authentication methods
Used by scp/sftp to do public/private key authentication
Send CCC (Clear Command Channel) after authentication
Same as TIMEOUT and CONNECTTIMEOUT, but with ms resolution
set to zero to disable the libcurl's decoding and thus pass the raw body data to the application even when it is encoded/compressed
Permission used when creating new files and directories on the remote server for protocols that support it, SFTP/SCP/FILE
Set the behaviour of POST when redirecting. Values must be set to one of CURL_REDIR* defines below. This used to be called CURLOPT_POST301
used by scp/sftp to verify the host's public key
Callback function for opening socket (instead of socket(2)). Optionally, callback is able change the address or refuse to connect returning CURL_SOCKET_BAD. The callback should have type curl_opensocket_callback
POST volatile input fields.
set transfer mode (;type=) when doing FTP via an HTTP proxy
Callback function for seeking in the input stream
(IPv6) Address scope
Collect certificate chain info and allow it to get retrievable with CURLINFO_CERTINFO after the transfer is complete. (Unfortunately) only working with OpenSSL-powered builds.
"name" and "pwd" to use when fetching.
"name" and "pwd" to use with Proxy when fetching.
Comma separated list of hostnames defining no-proxy zones. These should match both hostnames directly, and hostnames within a domain. For example, local.com will match local.com and www.local.com, but NOT notlocal.com or www.notlocal.com. For compatibility with other implementations of this, .local.com will be considered to be the same as local.com. A single * is the only valid wildcard, and effectively disables the use of proxy.
block size for TFTP transfers
set the bitmask for the protocols that are allowed to be used for the transfer, which thus helps the app which takes URLs from users or other external inputs and want to restrict what protocol(s) to deal with. Defaults to CURLPROTO_ALL.
set the bitmask for the protocols that libcurl is allowed to follow to, as a subset of the CURLOPT_PROTOCOLS ones. That means the protocol needs to be set in both bitmasks to be allowed to get redirected to. Defaults to all protocols except FILE and SCP.
set the SSH knownhost file name to use
set the SSH host key callback, must point to a curl_sshkeycallback function
set the SSH host key callback custom pointer
set the SMTP mail originator
set the SMTP mail receiver(s)
RTSP request method (OPTIONS, SETUP, PLAY, etc...)
The RTSP session identifier
The RTSP stream URI
The Transport: header to use in RTSP requests
Manually initialize the client RTSP CSeq for this handle
Manually initialize the server RTSP CSeq for this handle
The stream to pass to INTERLEAVEFUNCTION.
Let the application define a custom write method for RTP data
Turn on wildcard matching
Directory matching callback called before downloading of an individual file (chunk) started
Directory matching callback called after the file (chunk) was downloaded, or skipped
Change match (fnmatch-like) callback for wildcard matching
Let the application define custom chunk data pointer
FNMATCH_FUNCTION user pointer
send linked-list of name:port:address sets
Set a username for authenticated TLS
Set a password for authenticated TLS
Set authentication type for authenticated TLS
the last unused
Below here follows defines for the CURLOPT_IPRESOLVE option. If a host name resolves addresses using more than one IP protocol version, this option might be handy to force libcurl to use a specific IP version.
three convenient "aliases" that follow the name scheme better
These enums are for use with the CURLOPT_HTTP_VERSION option.
Public API enums for RTSP requests
These enums are for use with the CURLOPT_NETRC option.
symbols to use with CURLOPT_POSTREDIR. CURL_REDIR_POST_301 and CURL_REDIR_POST_302 can be bitwise ORed so that CURL_REDIR_POST_301 | CURL_REDIR_POST_302 == CURL_REDIR_POST_ALL
curl_strequal() and curl_strnequal() are subject for removal in a future libcurl, see lib/README.curlx for details
ditto curl_strequal() and curl_strnequal() are subject for removal in a future libcurl, see lib/README.curlx for details
use this for multipart formpost building Returns code for curl_formadd()
callback function for curl_formget() The void *arg pointer will be the one passed as second argument to curl_formget(). The character buffer passed to it must not be freed. Should return the buffer length passed to it as the argument "len" on success.
the previous version:
the previous version
linked-list structure for the CURLOPT_QUOTE option (and other)
info about the certificate chain, only for OpenSSL builds. Asked for with CURLOPT_CERTINFO / CURLINFO_CERTINFO linked-list structure for the CURLOPT_QUOTE option (and other)
Fill in new entries below here!
CURLINFO_RESPONSE_CODE is the new name for the option previously known as CURLINFO_HTTP_CODE
Setup defines, protos etc for the sharing stuff. Different data locks for a single share
Different lock access types
pass in a user data pointer used in the lock/unlock callback functions
Structures for querying information about the curl library at runtime.
The ' CURLVERSION_NOW' is the symbolic name meant to be used by basically all programs ever that want to get version information. It is meant to be a built-in version number for what kind of struct the caller expects. If the struct ever changes, we redefine the NOW to another enum from above.
age of the returned struct
OS/ host/cpu/machine when configured
bitmask, see defines below
human readable string
not used anymore, always 0
human readable string
protocols is terminated by an entry with a NULL protoname
The fields below this were added in CURLVERSION_SECOND
This field was added in CURLVERSION_THIRD
These field were added in CURLVERSION_FOURTH Same as 'libiconv_version' if built with HAVE_ICONV
human readable string
kerberos auth is supported
SSL options are present
libz features are present
NTLM auth is supported
Negotiate auth support
built with debug capabilities
asynchronous dns resolves
supports files bigger than 2GB
International Domain Names support
SSPI is supported
character conversions supported
debug memory tracking supported
TLS-SRP auth is supported
please call curl_multi_perform() or curl_multi_socket*() soon
the passed-in handle is not a valid CURLM handle
an easy handle was not good/valid
if you ever get this, you're in deep sh*t
this is a libcurl bug
the passed in socket argument did not match
curl_multi_setopt() with unsupported option
just to make code nicer when using curl_multi_socket() you can now check for CURLM_CALL_MULTI_SOCKET too in the same style it works for curl_multi_perform() and CURLM_CALL_MULTI_PERFORM
private socket pointer
private callback pointer
This macro below was added in 7.16.3 to push users who recompile to use the new curl_multi_socket_action() instead of the old curl_multi_socket()
This is the socket callback function pointer
This is the argument passed to the socket callback
set to 1 to enable pipelining for this multi handle
This is the timer callback function pointer
This is the argument passed to the timer callback
maximum number of entries in the connection cache