curl/docs/libcurl/opts/CURLOPT_IOCTLDATA.md
Daniel Stenberg e3fe020089
docs/libcurl: generate PROTOCOLS from meta-data
Remove the PROTOCOLS section from the source files completely and
instead generate them based on the header data in the curldown files.

It also generates TLS backend information for options marked for TLS as
protocol.

Closes #13175
2024-03-23 18:13:03 +01:00

71 lines
1.3 KiB
Markdown

---
c: Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
SPDX-License-Identifier: curl
Title: CURLOPT_IOCTLDATA
Section: 3
Source: libcurl
See-also:
- CURLOPT_IOCTLFUNCTION (3)
- CURLOPT_SEEKFUNCTION (3)
Protocol:
- All
---
# NAME
CURLOPT_IOCTLDATA - pointer passed to I/O callback
# SYNOPSIS
~~~c
#include <curl/curl.h>
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_IOCTLDATA, void *pointer);
~~~
# DESCRIPTION
Pass the *pointer* that is untouched by libcurl and passed as the 3rd
argument in the ioctl callback set with CURLOPT_IOCTLFUNCTION(3).
# DEFAULT
By default, the value of this parameter is NULL.
# EXAMPLE
~~~c
#include <unistd.h> /* for lseek */
struct data {
int fd; /* our file descriptor */
};
static curlioerr ioctl_callback(CURL *handle, int cmd, void *clientp)
{
struct data *io = (struct data *)clientp;
if(cmd == CURLIOCMD_RESTARTREAD) {
lseek(io->fd, 0, SEEK_SET);
return CURLIOE_OK;
}
return CURLIOE_UNKNOWNCMD;
}
int main(void)
{
struct data ioctl_data;
CURL *curl = curl_easy_init();
if(curl) {
curl_easy_setopt(curl, CURLOPT_IOCTLFUNCTION, ioctl_callback);
curl_easy_setopt(curl, CURLOPT_IOCTLDATA, &ioctl_data);
}
}
~~~
# AVAILABILITY
Added in 7.12.3. Deprecated since 7.18.0.
# RETURN VALUE
Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION if not.