CURLOPT_POST(3) Library Functions Manual CURLOPT_POST(3)
NAME
CURLOPT_POST - make an HTTP POST
SYNOPSIS
#include <curl/curl.h>
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_POST, long post);
DESCRIPTION
A parameter set to 1 tells libcurl to do a regular HTTP post. This also
makes libcurl use a "Content-Type: application/x-www-form-urlencoded"
header. This is 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 with CURLOPT_HTTPHEADER(3).
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 an 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. (Since 7.66.0, libcurl
automatically uses chunked encoding for POSTs if the size is unknown.)
When setting CURLOPT_POST(3) to 1, libcurl automatically sets
CURLOPT_NOBODY(3) and CURLOPT_HTTPGET(3) to 0.
If you issue a POST request and then want to make a HEAD or GET using
the same reused handle, you must explicitly set the new request type
using CURLOPT_NOBODY(3) or CURLOPT_HTTPGET(3) or similar.
When setting CURLOPT_POST(3) to 0, libcurl resets the request type to
the default to disable the POST. Typically that means gets reset to
GET. Instead you should set a new request type explicitly as described
above.
DEFAULT
0, disabled
PROTOCOLS
This functionality affects http only
EXAMPLE
int main(void)
{
CURL *curl = curl_easy_init();
if(curl) {
CURLcode res;
curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/foo.bin");
curl_easy_setopt(curl, CURLOPT_POST, 1L);
/* set up the read callback with CURLOPT_READFUNCTION */
res = curl_easy_perform(curl);
curl_easy_cleanup(curl);
}
}
AVAILABILITY
Added in curl 7.1
RETURN VALUE
curl_easy_setopt(3) returns a CURLcode indicating success or error.
CURLE_OK (0) means everything was OK, non-zero means an error occurred,
see libcurl-errors(3).
SEE ALSO
CURLOPT_HTTPPOST(3), CURLOPT_POSTFIELDS(3), CURLOPT_UPLOAD(3)
libcurl 2025-02-08 CURLOPT_POST(3)
curl 8.12.0 - Generated Mon Feb 17 18:09:09 CST 2025