NAME

       CURLOPT_UPLOAD_BUFFERSIZE - upload buffer size

SYNOPSIS

       #include <curl/curl.h>

       CURLcode curl_easy_setopt(CURL *handle, CURLOPT_UPLOAD_BUFFERSIZE, long size);

DESCRIPTION

       Pass a long specifying your preferred size (in bytes) for the upload buffer in libcurl. It
       makes libcurl uses a larger buffer that gets passed to the next layer in the stack to  get
       sent  off.  In  some  setups and for some protocols, there's a huge performance benefit of
       having a larger upload buffer.

       This is just treated as a request, not an order. You cannot be guaranteed to actually  get
       the given size.

       The  upload  buffer size is by default 64 kilobytes. The maximum buffer size allowed to be
       set is 2 megabytes. The minimum buffer size allowed to be set is 16 kilobytes.

       Since curl 7.61.1 the upload buffer is allocated on-demand - so if the handle is not  used
       for upload, this buffer will not be allocated at all.

       DO  NOT  set this option on a handle that is currently used for an active transfer as that
       may lead to unintended consequences.

DEFAULT

       65536 bytes

PROTOCOLS

       All

EXAMPLE

       CURL *curl = curl_easy_init();
       if(curl) {
         curl_easy_setopt(curl, CURLOPT_URL, "sftp://example.com/foo.bin");

         /* ask libcurl to allocate a larger upload buffer */
         curl_easy_setopt(curl, CURLOPT_UPLOAD_BUFFERSIZE, 120000L);

         ret = curl_easy_perform(curl);

         curl_easy_cleanup(curl);
       }

AVAILABILITY

       Added in 7.62.0.

RETURN VALUE

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

SEE ALSO

       CURLOPT_BUFFERSIZE(3), CURLOPT_READFUNCTION(3),