curl_mime_headers - set a mime part's custom headers

Added in curl 7.56.0

curl_mime_headers(3) sets a mime part's custom headers. part is the part's handle to assign the custom headers list to. headers is the head of a list of custom headers; it may be set to NULL to remove a previously attached custom header list. take_ownership: when non-zero, causes the list to be freed upon replacement or mime structure deletion; in this case the list must not be freed explicitly. Setting a part's custom headers list multiple times is valid: only the value set by the last call is retained.

int main(void) { struct curl_slist *headers = NULL; CURL *easy = curl_easy_init(); curl_mime *mime; curl_mimepart *part; headers = curl_slist_append(headers, "Custom-Header: mooo"); mime = curl_mime_init(easy); part = curl_mime_addpart(mime); /* use these headers in the part, takes ownership */ curl_mime_headers(part, headers, 1); /* pass on this data */ curl_mime_data(part, "12345679", CURL_ZERO_TERMINATED); /* set name */ curl_mime_name(part, "numbers"); /* Post and send it. */ curl_easy_setopt(easy, CURLOPT_MIMEPOST, mime); curl_easy_setopt(easy, CURLOPT_URL, "https://example.com"); curl_easy_perform(easy); }

curl_mime_headers - set a mime part's custom headers

This functionality affects http, imap and smtp

This function returns a CURLcode indicating success or error. CURLE_OK (0) means everything was OK, non-zero means an error occurred, see libcurl-errors(3). If CURLOPT_ERRORBUFFER(3) was set with curl_easy_setopt(3) there can be an error message stored in the error buffer when non-zero is returned.

curl_mime_addpart(3), curl_mime_name(3) libcurl 2025-06-16 curl_mime_headers(3)

#include <curl/curl.h> CURLcode curl_mime_headers(curl_mimepart *part, struct curl_slist *headers, int take_ownership);