---
name: "CURLINFO_PROTOCOL"
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/CURLINFO_PROTOCOL"
---

# CURLINFO\_PROTOCOL(3)

URL scheme used in transfer

## NAME

CURLINFO\_PROTOCOL - URL scheme used in transfer

## SYNOPSIS

```
#include <curl/curl.h>
CURLcode curl_easy_getinfo(CURL *handle, CURLINFO_PROTOCOL, long *p);
```

## DESCRIPTION

This option is deprecated. We strongly recommend using *[CURLINFO\_SCHEME(3)](/CURLINFO_SCHEME/3.md)* instead, because this option cannot return all possible schemes. The scheme might also sometimes be referred to as the protocol.

Pass a pointer to a long to receive the scheme used in the last transfer. The returned value is set to one of these values:

```
CURLPROTO_DICT, CURLPROTO_FILE, CURLPROTO_FTP, CURLPROTO_FTPS,
CURLPROTO_GOPHER, CURLPROTO_HTTP, CURLPROTO_HTTPS, CURLPROTO_IMAP,
CURLPROTO_IMAPS, CURLPROTO_LDAP, CURLPROTO_LDAPS, CURLPROTO_POP3,
CURLPROTO_POP3S, CURLPROTO_RTMP, CURLPROTO_RTMPE, CURLPROTO_RTMPS,
CURLPROTO_RTMPT, CURLPROTO_RTMPTE, CURLPROTO_RTMPTS, CURLPROTO_RTSP,
CURLPROTO_SCP, CURLPROTO_SFTP, CURLPROTO_SMTP, CURLPROTO_SMTPS,
CURLPROTO_TELNET, CURLPROTO_TFTP, CURLPROTO_MQTT
```

## PROTOCOLS

This functionality affects all supported protocols

## EXAMPLE

```
int main(void)
{
  CURL *curl = curl_easy_init();
  if(curl) {
    CURLcode result;
    curl_easy_setopt(curl, CURLOPT_URL, "https://example.com");
    result = curl_easy_perform(curl);
    if(result == CURLE_OK) {
      long scheme;
      curl_easy_getinfo(curl, CURLINFO_PROTOCOL, &scheme);
    }
    curl_easy_cleanup(curl);
  }
}
```

## DEPRECATED

Deprecated since 7.85.0.

## AVAILABILITY

Added in curl 7.52.0

## RETURN VALUE

*[curl\_easy\_getinfo(3)](/curl_easy_getinfo/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

[**CURLINFO\_RESPONSE\_CODE**(3)](/CURLINFO_RESPONSE_CODE/3.md), [**curl\_easy\_getinfo**(3)](/curl_easy_getinfo/3.md), [**curl\_easy\_setopt**(3)](/curl_easy_setopt/3.md)