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CURLOPT_POSTFIELDS(3)               libcurl              CURLOPT_POSTFIELDS(3)


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 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 behavior 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.

       libcurl will use assume 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 will add 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

       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 */
         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),
       CURLOPT_MIMEPOST(3), CURLOPT_UPLOAD(3),

ibcurl 8.1.2                    April 26, 2023           CURLOPT_POSTFIELDS(3)

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