CURLOPT\_SEEKDATA(3) Library Functions Manual CURLOPT\_SEEKDATA(3)

# [NAME](#NAME)

CURLOPT\_SEEKDATA - pointer passed to the seek callback

# [SYNOPSIS](#SYNOPSIS)

```
#include <curl/curl.h>
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_SEEKDATA, void *pointer);
```

# [DESCRIPTION](#DESCRIPTION)

Data *pointer* to pass to the seek callback function. If you use the [*CURLOPT\_SEEKFUNCTION(3)*](/man/os/curl/CURLOPT_SEEKFUNCTION.3) option, this is the pointer you get as input.

# [DEFAULT](#DEFAULT)

If you do not set this, NULL is passed to the callback.

# [PROTOCOLS](#PROTOCOLS)

This functionality affects ftp, http and sftp

# [EXAMPLE](#EXAMPLE)

```
#include <unistd.h> /* for lseek() */
struct data {


  int our_fd;
};
static int seek_cb(void *clientp, curl_off_t offset, int origin)
{


  struct data *d = (struct data *)clientp;


  lseek(d->our_fd, offset, origin);


  return CURL_SEEKFUNC_OK;
}
int main(void)
{


  struct data seek_data;


  CURL *curl = curl_easy_init();


  if(curl) {


    curl_easy_setopt(curl, CURLOPT_SEEKFUNCTION, seek_cb);


    curl_easy_setopt(curl, CURLOPT_SEEKDATA, &seek_data);


  }
}
```

# [AVAILABILITY](#AVAILABILITY)

Added in curl 7.18.0

# [RETURN VALUE](#RETURN_VALUE)

# [SEE ALSO](#SEE_ALSO)

[**CURLOPT\_DEBUGFUNCTION**(3)](/man/os/curl/CURLOPT_DEBUGFUNCTION.3), [**CURLOPT\_IOCTLFUNCTION**(3)](/man/os/curl/CURLOPT_IOCTLFUNCTION.3), [**CURLOPT\_SEEKFUNCTION**(3)](/man/os/curl/CURLOPT_SEEKFUNCTION.3), [**CURLOPT\_STDERR**(3)](/man/os/curl/CURLOPT_STDERR.3)

2026-09-24 libcurl

---

Document: CURLOPT_SEEKDATA(3) from curl 8.22.0-r3 (Chainguard OS)
Source: https://github.com/curl/curl.git