curl_slist_append(3) Library Functions Manual curl_slist_append(3)
NAME
curl_slist_append - add a string to an slist
SYNOPSIS
#include <curl/curl.h>
struct curl_slist *curl_slist_append(struct curl_slist *list,
const char *string);
DESCRIPTION
curl_slist_append(3) appends a string to a linked list of strings. The
existing list should be passed as the first argument and the new list
is returned from this function. Pass in NULL in the list argument to
create a new list. The specified string has been appended when this
function returns. curl_slist_append(3) copies the string. The string
argument must be a valid string pointer and cannot be NULL.
The list should be freed (after usage) with curl_slist_free_all(3).
Its nodes and pointed content may not be altered outside this function.
PROTOCOLS
This functionality affects all supported protocols
EXAMPLE
int main(void)
{
CURL *handle = curl_easy_init();
struct curl_slist *slist = NULL;
struct curl_slist *temp = NULL;
slist = curl_slist_append(slist, "pragma:");
if(!slist)
return -1;
temp = curl_slist_append(slist, "Accept:");
if(!temp) {
curl_slist_free_all(slist);
return -1;
}
slist = temp;
curl_easy_setopt(handle, CURLOPT_HTTPHEADER, slist);
curl_easy_perform(handle);
curl_slist_free_all(slist); /* free the list again */
}
AVAILABILITY
Added in curl 7.1
RETURN VALUE
A null pointer is returned if anything went wrong, otherwise the new
list pointer is returned. To avoid overwriting an existing non-empty
list on failure, the new list should be returned to a temporary
variable which can be tested for NULL before updating the original list
pointer.
SEE ALSO
curl_slist_free_all(3)
libcurl 2026-03-23 curl_slist_append(3)
curl 8.19.0 - Generated Tue Mar 24 15:46:23 CDT 2026