curl_slist_append(3) Introduction to Library Functions 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 2026-01-08 curl_slist_append(3)