Provided by: libcurl4-doc_7.68.0-1ubuntu2.25_all 

NAME
CURLOPT_POSTFIELDS - specify data to POST to server
SYNOPSIS
#include <curl/curl.h>
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_POSTFIELDS, char *postdata);
DESCRIPTION
Pass a char * as parameter, pointing to the full data to send in an HTTP POST operation. You must make
sure that the data is formatted the way you want the server to receive it. libcurl will not convert or
encode it for you in any way. For example, the web server may assume that this data is url-encoded.
The data pointed to is NOT copied by the library: as a consequence, it must be preserved by the calling
application until the associated transfer finishes. This behaviour can be changed (so libcurl does copy
the data) by setting the CURLOPT_COPYPOSTFIELDS(3) option.
This POST is a normal application/x-www-form-urlencoded kind (and libcurl will set that Content-Type by
default when this option is used), which is commonly used by HTML forms. Change Content-Type with
CURLOPT_HTTPHEADER(3).
You can use curl_easy_escape(3) to url-encode your data, if necessary. It returns a pointer to an encoded
string that can be passed as postdata.
Using CURLOPT_POSTFIELDS(3) implies setting CURLOPT_POST(3) to 1.
If CURLOPT_POSTFIELDS(3) is explicitly set to NULL then libcurl will get the POST data from the read
callback. If you want to send a zero-byte POST set CURLOPT_POSTFIELDS(3) to an empty string, or set
CURLOPT_POST(3) to 1 and CURLOPT_POSTFIELDSIZE(3) to 0.
Using POST with HTTP 1.1 implies the use of a "Expect: 100-continue" header, and libcurl will add that
header automatically if the POST is either known to be larger than 1024 bytes or if the expected size is
unknown. You can disable this header with CURLOPT_HTTPHEADER(3) as usual.
To make multipart/formdata posts (aka RFC2388-posts), check out the CURLOPT_HTTPPOST(3) option combined
with curl_formadd(3).
DEFAULT
NULL
PROTOCOLS
HTTP
EXAMPLE
CURL *curl = curl_easy_init();
if(curl) {
const char *data = "data to send";
curl_easy_setopt(curl, CURLOPT_URL, "http://example.com");
/* size of the POST data */
curl_easy_setopt(curl, CURLOPT_POSTFIELDSIZE, 12L);
/* pass in a pointer to the data - libcurl will not copy */
curl_easy_setopt(curl, CURLOPT_POSTFIELDS, data);
curl_easy_perform(curl);
}
AVAILABILITY
Always
RETURN VALUE
Returns CURLE_OK
SEE ALSO
CURLOPT_POSTFIELDSIZE(3), CURLOPT_READFUNCTION(3),
libcurl 7.68.0 May 21, 2018 CURLOPT_POSTFIELDS(3)