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curl_easy_pause(3)                             libcurl Manual                             curl_easy_pause(3)



NAME
       curl_easy_pause - pause and unpause a connection

SYNOPSIS
       #include <curl/curl.h>

       CURLcode curl_easy_pause(CURL *handle, int bitmask );


DESCRIPTION
       Using  this function, you can explicitly mark a running connection to get paused, and you can unpause
       a connection that was previously paused.

       A connection can be paused by using this function or by letting  the  read  or  the  write  callbacks
       return  the proper magic return code (CURL_READFUNC_PAUSE and CURL_WRITEFUNC_PAUSE). A write callback
       that returns pause signals to the library that it couldn't take care of any data  at  all,  and  that
       data will then be delivered again to the callback when the writing is later unpaused.

       NOTE:  while  it  may  feel  tempting,  take  care and notice that you cannot call this function from
       another thread.

       When this function is called to unpause reading, the chance is high that  you  will  get  your  write
       callback called before this function returns.

       The  handle  argument is of course identifying the handle that operates on the connection you want to
       pause or unpause.

       The bitmask argument is a set of bits that sets the new state of the connection. The  following  bits
       can be used:

       CURLPAUSE_RECV
              Pause receiving data. There will be no data received on this connection until this function is
              called again without this bit set. Thus, the write callback (CURLOPT_WRITEFUNCTION)  won't  be
              called.

       CURLPAUSE_SEND
              Pause  sending  data.  There  will  be  no data sent on this connection until this function is
              called again without this bit set. Thus, the read  callback  (CURLOPT_READFUNCTION)  won't  be
              called.

       CURLPAUSE_ALL
              Convenience define that pauses both directions.

       CURLPAUSE_CONT
              Convenience define that unpauses both directions

RETURN VALUE
       CURLE_OK  (zero)  means  that the option was set properly, and a non-zero return code means something
       wrong occurred after the new state was set.  See the libcurl-errors(3) man page  for  the  full  list
       with descriptions.

AVAILABILITY
       This  function  was  added  in libcurl 7.18.0. Before this version, there was no explicit support for
       pausing transfers.

MEMORY USE
       When pausing a read by returning the magic return code from  a  write  callback,  the  read  data  is
       already in libcurl's internal buffers so it'll have to keep it in an allocated buffer until the read-ing reading
       ing is again unpaused using this function.

       If the downloaded data is compressed and is asked to  get  uncompressed  automatically  on  download,
       libcurl  will  continue  to  uncompress the entire downloaded chunk and it will cache the data uncom-pressed. uncompressed.
       pressed. This has the side- effect that if you download something that is compressed a  lot,  it  can
       result  in  a  very large data amount needing to be allocated to save the data during the pause. This
       said, you should probably consider not using paused reading if you allow libcurl to  uncompress  data
       automatically.

SEE ALSO
       curl_easy_cleanup(3), curl_easy_reset(3)



libcurl 7.18.0                                   17 Dec 2007                              curl_easy_pause(3)