---
name: "curl_slist_append"
section: "3"
platform: "linux"
package: "curl"
version: "8.23.0-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux", "macos"]
url: "https://new.carta.tech/curl_slist_append"
---

# curl\_slist\_append(3)

add a string to an slist

## 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)](/curl_slist_append/3.md)* 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)](/curl_slist_append/3.md)* 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)](/curl_slist_free_all/3.md)*. 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)](/curl_slist_free_all/3.md)