curl_slist_append - add a string to an slist

Added in curl 7.1

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 list should be freed again (after usage) with curl_slist_free_all(3).

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 */ }

curl_slist_append - add a string to an slist

This functionality affects all supported protocols

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.

curl_slist_free_all(3) libcurl 2025-06-16 curl_slist_append(3)

#include <curl/curl.h> struct curl_slist *curl_slist_append(struct curl_slist *list, const char *string);