curlopt_ioctlfunction(3) [mojave man page]

CURLOPT_IOCTLFUNCTION(3)				     curl_easy_setopt options					  CURLOPT_IOCTLFUNCTION(3)

NAME

       CURLOPT_IOCTLFUNCTION - callback for I/O operations

SYNOPSIS

       #include <curl/curl.h>

       typedef enum {
	 CURLIOE_OK,		/* I/O operation successful */
	 CURLIOE_UNKNOWNCMD,	/* command was unknown to callback */
	 CURLIOE_FAILRESTART,	/* failed to restart the read */
	 CURLIOE_LAST		/* never use */
       } curlioerr;

       typedef enum  {
	 CURLIOCMD_NOP, 	/* no operation */
	 CURLIOCMD_RESTARTREAD, /* restart the read stream from start */
	 CURLIOCMD_LAST 	/* never use */
       } curliocmd;

       curlioerr ioctl_callback(CURL *handle, int cmd, void *clientp);

       CURLcode curl_easy_setopt(CURL *handle, CURLOPT_IOCTLFUNCTION, ioctl_callback);

DESCRIPTION

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

       This  callback function gets called by libcurl when something special I/O-related needs to be done that the library can't do by itself. For
       now, rewinding the read data stream is the only action it can request. The rewinding of the read data stream may be necessary when doing  a
       HTTP PUT or POST with a multi-pass authentication method.

       The callback MUST return CURLIOE_UNKNOWNCMD if the input cmd is not CURLIOCMD_RESTARTREAD.

       The clientp argument to the callback is set with the CURLOPT_IOCTLDATA(3) option.

       This  option  is deprecated! Do not use it. Use CURLOPT_SEEKFUNCTION(3) instead to provide seeking! If CURLOPT_SEEKFUNCTION(3) is set, this
       parameter will be ignored when seeking.

DEFAULT

       By default, this parameter is set to NULL. Not used.

PROTOCOLS

       Used with HTTP

EXAMPLE

       TODO

AVAILABILITY

       Added in 7.12.3

RETURN VALUE

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

SEE ALSO

       CURLOPT_IOCTLDATA(3), CURLOPT_SEEKFUNCTION(3),

libcurl 7.54.0							 February 03, 2016					  CURLOPT_IOCTLFUNCTION(3)

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)