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curl_easy_pause(3) [osx man page]

curl_easy_pause(3)						  libcurl Manual						curl_easy_pause(3)

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 reading 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 uncompressed. This has the side- effect that if you download something that is com- pressed 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)

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CURLOPT_WRITEFUNCTION(3)				     curl_easy_setopt options					  CURLOPT_WRITEFUNCTION(3)

CURLOPT_WRITEFUNCTION - set callback for writing received data SYNOPSIS
#include <curl/curl.h> size_t write_callback(char *ptr, size_t size, size_t nmemb, void *userdata); CURLcode curl_easy_setopt(CURL *handle, CURLOPT_WRITEFUNCTION, write_callback); DESCRIPTION
Pass a pointer to your callback function, which should match the prototype shown above. This callback function gets called by libcurl as soon as there is data received that needs to be saved. ptr points to the delivered data, and the size of that data is size multiplied with nmemb. The callback function will be passed as much data as possible in all invokes, but you must not make any assumptions. It may be one byte, it may be thousands. The maximum amount of body data that will be passed to the write callback is defined in the curl.h header file: CURL_MAX_WRITE_SIZE (the usual default is 16K). If CURLOPT_HEADER(3) is enabled, which makes header data get passed to the write callback, you can get up to CURL_MAX_HTTP_HEADER bytes of header data passed into it. This usually means 100K. This function may be called with zero bytes data if the transferred file is empty. The data passed to this function will not be zero terminated! Set the userdata argument with the CURLOPT_WRITEDATA(3) option. Your callback should return the number of bytes actually taken care of. If that amount differs from the amount passed to your callback function, it'll signal an error condition to the library. This will cause the transfer to get aborted and the libcurl function used will return CURLE_WRITE_ERROR. If your callback function returns CURL_WRITEFUNC_PAUSE it will cause this transfer to become paused. See curl_easy_pause(3) for further details. Set this option to NULL to get the internal default function used instead of your callback. The internal default function will write the data to the FILE * given with CURLOPT_WRITEDATA(3). DEFAULT
libcurl will use 'fwrite' as a callback by default. PROTOCOLS
For all protocols AVAILABILITY
Support for the CURL_WRITEFUNC_PAUSE return code was added in version 7.18.0. RETURN VALUE
This will return CURLE_OK. EXAMPLE
A common technique is to use this callback to store the incoming data into a dynamically growing allocated buffer. Like in the getinmemory example: SEE ALSO
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