A parameter set to 1 tells libcurl to do a regular HTTP post. This will also
make the library use a "Content-Type: application/x-www-form-urlencoded"
header. (This is by far the most commonly used POST method).
Use one of CURLOPT_POSTFIELDS(3) or CURLOPT_COPYPOSTFIELDS(3)
options to specify what data to post and CURLOPT_POSTFIELDSIZE(3) or
CURLOPT_POSTFIELDSIZE_LARGE(3) to set the data size.
Optionally, you can provide data to POST using the
CURLOPT_READFUNCTION(3) and CURLOPT_READDATA(3) options but then
you must make sure to not set CURLOPT_POSTFIELDS(3) to anything but
NULL. When providing data with a callback, you must transmit it using chunked
transfer-encoding or you must set the size of the data with the
CURLOPT_POSTFIELDSIZE(3) or CURLOPT_POSTFIELDSIZE_LARGE(3)
options. To enable chunked encoding, you simply pass in the appropriate
Transfer-Encoding header, see the post-callback.c example.
You can override the default POST Content-Type: header by setting your own
Using POST with HTTP 1.1 implies the use of a "Expect: 100-continue" header.
You can disable this header with CURLOPT_HTTPHEADER(3) as usual.
If you use POST to a HTTP 1.1 server, you can send data without knowing the
size before starting the POST if you use chunked encoding. You enable this by
adding a header like "Transfer-Encoding: chunked" with
CURLOPT_HTTPHEADER(3). With HTTP 1.0 or without chunked transfer, you
must specify the size in the request.
When setting CURLOPT_POST(3) to 1, it will automatically set
CURLOPT_NOBODY(3) to 0.
If you issue a POST request and then want to make a HEAD or GET using the same
re-used handle, you must explicitly set the new request type using
CURLOPT_NOBODY(3) or CURLOPT_HTTPGET(3) or similar.