docs: formpost needs the full size at start of upload

\fBcurl\fP -F password=@/etc/passwd www.mypasswords.com

To read content from stdin instead of a file, use - as the filename. This goes

for both @ and < constructs.

for both @ and < constructs. Unfortunately it does not support reading the

file from a named pipe or similar, as it needs the full size before the

transfer starts.

You can also tell curl what Content-Type to use by using 'type=', in a manner

similar to:

.\" *                            | (__| |_| |  _ <| |___

.\" *                             \___|\___/|_| \_\_____|

.\" *

.\" * Copyright (C) 1998 - 2014, Daniel Stenberg, <daniel@haxx.se>, et al.

.\" * Copyright (C) 1998 - 2015, Daniel Stenberg, <daniel@haxx.se>, et al.

.\" *

.\" * This software is licensed as described in the file COPYING, which

.\" * you should have received as part of this distribution. The terms

providing multiple \fBCURLFORM_FILE\fP arguments each followed by the filename

(and each \fICURLFORM_FILE\fP is allowed to have a

\fICURLFORM_CONTENTTYPE\fP).

The given upload file has to exist in its full in the file system already when

the upload starts, as libcurl needs to read the correct file size beforehand.

.IP CURLFORM_CONTENTTYPE

is used in combination with \fICURLFORM_FILE\fP. Followed by a pointer to a

string which provides the content-type for this part, possibly instead of an