NAME

       CURLOPT_POSTFIELDS - 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 data buffer to use in an HTTP POST operation. The data must
       be formatted and encoded the way you want the server to receive it. libcurl does not convert or encode it
       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 behavior can be changed (so libcurl does copy
       the data) by instead using the CURLOPT_COPYPOSTFIELDS(3) option.

       This POST is a normal application/x-www-form-urlencoded kind  (and  libcurl  sets  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  gets  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.

       libcurl  assumes   this   option   points   to   a   null-terminated   string   unless   you   also   set
       CURLOPT_POSTFIELDSIZE(3)  to  specify the length of the provided data, which then is strictly required if
       you want to send off null bytes included in the data.

       Using POST with HTTP 1.1 implies the use of a "Expect: 100-continue" header, and libcurl adds that header
       automatically if the POST is either known to be larger than 1MB or if the expected size is  unknown.  You
       can disable this header with CURLOPT_HTTPHEADER(3) as usual.

       To   make   multipart/formdata   posts,   check   out   the   CURLOPT_MIMEPOST(3)  option  combined  with
       curl_mime_init(3).

DEFAULT

       NULL

PROTOCOLS

       HTTP

EXAMPLE

       /* send an application/x-www-form-urlencoded POST */
       int main(void)
       {
         CURL *curl = curl_easy_init();
         if(curl) {
           const char *data = "data to send";

           curl_easy_setopt(curl, CURLOPT_URL, "https://example.com");

           /* size of the POST data if strlen() is not good enough */
           curl_easy_setopt(curl, CURLOPT_POSTFIELDSIZE, 12L);

           /* pass in a pointer to the data - libcurl does not copy */
           curl_easy_setopt(curl, CURLOPT_POSTFIELDS, data);

           curl_easy_perform(curl);
         }

         /* send an application/json POST */
         curl = curl_easy_init();
         if(curl) {
           const char *json = "{
           struct curl_slist *slist1 = NULL;
           slist1 = curl_slist_append(slist1, "Content-Type: application/json");
           slist1 = curl_slist_append(slist1, "Accept: application/json");

           /* set custom headers */
           curl_easy_setopt(curl, CURLOPT_HTTPHEADER, slist1);

           curl_easy_setopt(curl, CURLOPT_URL, "https://example.com");

           /* pass in a pointer to the data - libcurl does not copy */
           curl_easy_setopt(curl, CURLOPT_POSTFIELDS, json);

           curl_easy_perform(curl);
         }
       }

AVAILABILITY

       Always

RETURN VALUE

       Returns CURLE_OK

SEE ALSO

       CURLOPT_COPYPOSTFIELDS(3),   CURLOPT_MIMEPOST(3),   CURLOPT_POSTFIELDSIZE(3),    CURLOPT_READFUNCTION(3),
       CURLOPT_UPLOAD(3)

ibcurl 8.5.0                                    December 04, 2023                          CURLOPT_POSTFIELDS(3)