RESUME_FROM: clarify what ftp uploads do

The numerical value passed to CURLOPT_RESUME_FROM for FTP uploads is
interpreted and used as position where to resume the _reading_ of the
local file and it will "blindly" append that data on the remote
file. This was certainly not clear in the docs previously.

Reported by: catalin
Bug: http://curl.haxx.se/bug/view.cgi?id=3048174

diff --git a/docs/libcurl/curl_easy_setopt.3 b/docs/libcurl/curl_easy_setopt.3
index 1704f6ad01bc41d2bf127fefa30fa442c9d5544c..aa2a3aff2a64d478f7c45c08cc10d1618d23c2b2 100644 (file)
--- a/docs/libcurl/curl_easy_setopt.3
+++ b/docs/libcurl/curl_easy_setopt.3
@@ -1539,6 +1539,10 @@ want the transfer to start from. Set this option to 0 to make the transfer
 start from the beginning (effectively disabling resume). For FTP, set this
 option to -1 to make the transfer start from the end of the target file
 (useful to continue an interrupted upload).
+
+When doing uploads with FTP, the resume position is where in the local/source
+file libcurl should try to resume the upload from and it will then append the
+source file to the remote target file.
 .IP CURLOPT_RESUME_FROM_LARGE
 Pass a curl_off_t as parameter. It contains the offset in number of bytes that
 you want the transfer to start from. (Added in 7.11.0)