---
name: "CURLOPT_FNMATCH_FUNCTION"
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/CURLOPT_FNMATCH_FUNCTION"
---

# CURLOPT\_FNMATCH\_FUNCTION(3)

wildcard match callback

## NAME

CURLOPT\_FNMATCH\_FUNCTION - wildcard match callback

## SYNOPSIS

```
#include <curl/curl.h>
int fnmatch_callback(void *ptr,
                     const char *pattern,
                     const char *string);
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_FNMATCH_FUNCTION,
                          fnmatch_callback);
```

## DESCRIPTION

Pass a pointer to your callback function, which should match the prototype shown above.

This callback is used for wildcard matching.

Return *CURL\_FNMATCHFUNC\_MATCH* if pattern matches the string, *CURL\_FNMATCHFUNC\_NOMATCH* if not or *CURL\_FNMATCHFUNC\_FAIL* if an error occurred.

## DEFAULT

NULL == an internal function for wildcard matching.

## PROTOCOLS

This functionality affects ftp only

## EXAMPLE

```
extern int string_match(const char *s1, const char *s2);
struct local_stuff {
  void *custom;
};
static int my_fnmatch(void *clientp,
                      const char *pattern, const char *string)
{
  struct local_stuff *data = clientp;
  printf("my pointer: %p\n", data->custom);
  if(string_match(pattern, string))
    return CURL_FNMATCHFUNC_MATCH;
  else
    return CURL_FNMATCHFUNC_NOMATCH;
}
int main(void)
{
  struct local_stuff local_data;
  CURL *curl = curl_easy_init();
  if(curl) {
    CURLcode result;
    curl_easy_setopt(curl, CURLOPT_URL, "ftp://ftp.example.com/file*");
    curl_easy_setopt(curl, CURLOPT_WILDCARDMATCH, 1L);
    curl_easy_setopt(curl, CURLOPT_FNMATCH_FUNCTION, my_fnmatch);
    curl_easy_setopt(curl, CURLOPT_FNMATCH_DATA, &local_data);
    result = curl_easy_perform(curl);
    curl_easy_cleanup(curl);
  }
}
```

## AVAILABILITY

Added in curl 7.21.0

## RETURN VALUE

*[curl\_easy\_setopt(3)](/curl_easy_setopt/3.md)* returns a CURLcode indicating success or error.

CURLE\_OK (0) means everything was OK, non-zero means an error occurred, see *[libcurl-errors(3)](/libcurl-errors/3.md)*.

## SEE ALSO

[**CURLOPT\_DEBUGFUNCTION**(3)](/CURLOPT_DEBUGFUNCTION/3.md), [**CURLOPT\_FNMATCH\_DATA**(3)](/CURLOPT_FNMATCH_DATA/3.md), [**CURLOPT\_WILDCARDMATCH**(3)](/CURLOPT_WILDCARDMATCH/3.md)