curlopt_opensocketfunction(3) [mojave man page]

CURLOPT_OPENSOCKETFUNCTION(3)				     curl_easy_setopt options				     CURLOPT_OPENSOCKETFUNCTION(3)

NAME

       CURLOPT_OPENSOCKETFUNCTION - set callback for opening sockets

SYNOPSIS

       #include <curl/curl.h>

       typedef enum  {
	 CURLSOCKTYPE_IPCXN,  /* socket created for a specific IP connection */
	 CURLSOCKTYPE_ACCEPT, /* socket created by accept() call */
	 CURLSOCKTYPE_LAST    /* never use */
       } curlsocktype;

       struct curl_sockaddr {
	 int family;
	 int socktype;
	 int protocol;
	 unsigned int addrlen;
	 struct sockaddr addr;
       };

       curl_socket_t opensocket_callback(void *clientp,
					 curlsocktype purpose,
					 struct curl_sockaddr *address);

       CURLcode curl_easy_setopt(CURL *handle, CURLOPT_OPENSOCKETFUNCTION, opensocket_callback);

DESCRIPTION

       Pass a pointer to your callback function, which should match the prototype shown above.

       This  callback  function gets called by libcurl instead of the socket(2) call. The callback's purpose argument identifies the exact purpose
       for this particular socket: CURLSOCKTYPE_IPCXN is for IP based connections and CURLSOCKTYPE_ACCEPT is for sockets created after accept()  -
       such as when doing active FTP. Future versions of libcurl may support more purposes.

       The clientp pointer contains whatever user-defined value set using the CURLOPT_OPENSOCKETDATA(3) function.

       The  callback  gets the resolved peer address as the address argument and is allowed to modify the address or refuse to connect completely.
       The callback function should return the newly created socket or CURL_SOCKET_BAD in case no connection could be established or another error
       was  detected.  Any  additional setsockopt(2) calls can of course be done on the socket at the user's discretion.  A CURL_SOCKET_BAD return
       value from the callback function will signal an unrecoverable error to libcurl and it will return CURLE_COULDNT_CONNECT from  the  function
       that triggered this callback.  This return code can be used for IP address blacklisting.

       If  you want to pass in a socket with an already established connection, pass the socket back with this callback and then use CURLOPT_SOCK-
       OPTFUNCTION(3) to signal that it already is connected.

DEFAULT

       The default behavior is the equivalent of this:
	  return socket(addr->family, addr->socktype, addr->protocol);

PROTOCOLS

       All

EXAMPLE

AVAILABILITY

       Added in 7.17.1.

RETURN VALUE

       Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION if not.

SEE ALSO

       CURLOPT_OPENSOCKETDATA(3), CURLOPT_SOCKOPTFUNCTION(3), CURLOPT_CLOSESOCKETFUNCTION(3),

libcurl 7.54.0							 February 03, 2016				     CURLOPT_OPENSOCKETFUNCTION(3)

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CURLOPT_PROGRESSFUNCTION(3)				     curl_easy_setopt options				       CURLOPT_PROGRESSFUNCTION(3)

NAME

       CURLOPT_PROGRESSFUNCTION - callback to progress meter function

SYNOPSIS

       #include <curl/curl.h>

       int progress_callback(void *clientp,
			     double dltotal,
			     double dlnow,
			     double ultotal,
			     double ulnow);

       CURLcode curl_easy_setopt(CURL *handle, CURLOPT_PROGRESSFUNCTION, progress_callback);

DESCRIPTION

       Pass a pointer to your callback function, which should match the prototype shown above.

       We encourage users to use the newer CURLOPT_XFERINFOFUNCTION(3) instead, if you can.

       This  function  gets called by libcurl instead of its internal equivalent with a frequent interval. While data is being transferred it will
       be called very frequently, and during slow periods like when nothing is being transferred it can slow down to about one call per second.

       clientp is the pointer set with CURLOPT_PROGRESSDATA(3), it is not used by libcurl but is only passed along from  the  application  to  the
       callback.

       The  callback  gets  told how much data libcurl will transfer and has transferred, in number of bytes. dltotal is the total number of bytes
       libcurl expects to download in this transfer. dlnow is the number of bytes downloaded so far. ultotal is the total number of bytes  libcurl
       expects to upload in this transfer. ulnow is the number of bytes uploaded so far.

       Unknown/unused  argument values passed to the callback will be set to zero (like if you only download data, the upload size will remain 0).
       Many times the callback will be called one or more times first, before it knows the data sizes so a program must be made to handle that.

       Returning a non-zero value from this callback will cause libcurl to abort the transfer and return CURLE_ABORTED_BY_CALLBACK.

       If you transfer data with the multi interface, this function will not be called during periods of idleness unless you call the  appropriate
       libcurl function that performs transfers.

       CURLOPT_NOPROGRESS(3) must be set to 0 to make this function actually get called.

DEFAULT

       By default, libcurl has an internal progress meter. That's rarely wanted by users.

PROTOCOLS

       All

EXAMPLE

       https://curl.haxx.se/libcurl/c/progressfunc.html

AVAILABILITY

       Always

RETURN VALUE

       Returns CURLE_OK.

SEE ALSO

       CURLOPT_VERBOSE(3), CURLOPT_NOPROGRESS(3),

libcurl 7.54.0							 February 03, 2016				       CURLOPT_PROGRESSFUNCTION(3)

Linux and UNIX Man Pages

curlopt_opensocketfunction(3) [mojave man page]

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