---
name: "libressl-SSL_CTX_set_info_callback"
section: "3"
platform: "linux"
package: "libressl"
version: "4.4.0-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/libressl-SSL_CTX_set_info_callback"
---

# libressl-SSL\_CTX\_set\_info\_callback(3)

handle information callback for SSL connections

## NAME

**SSL\_CTX\_set\_info\_callback**, **SSL\_CTX\_get\_info\_callback**, **SSL\_set\_info\_callback**, **SSL\_get\_info\_callback** – handle information callback for SSL connections

## SYNOPSIS

SSL Library (libssl, -lssl) libcrypto

**#include \<openssl/ssl.h\>**

*void*\

**SSL\_CTX\_set\_info\_callback**(*SSL\_CTX \*ctx*, *void (\*callback)(const SSL \*ssl, int where, int ret)*);

*void*\

**(\*SSL\_CTX\_get\_info\_callback(const SSL\_CTX \*ctx))**(*const SSL \*ssl*, *int where*, *int ret*);

*void*\

**SSL\_set\_info\_callback**(*SSL \*ssl*, *void (\*callback)(const SSL \*ssl, int where, int ret)*);

*void*\

**(\*SSL\_get\_info\_callback(const SSL \*ssl))**(*const SSL \*ssl*, *int where*, *int ret*);

## DESCRIPTION

**SSL\_CTX\_set\_info\_callback**() sets the *callback* function that can be used to obtain state information for SSL objects created from *ctx* during connection setup and use. The setting for *ctx* is overridden from the setting for a specific SSL object, if specified. When *callback* is NULL, no callback function is used.

**SSL\_set\_info\_callback**() sets the *callback* function that can be used to obtain state information for *ssl* during connection setup and use. When *callback* is NULL, the callback setting currently valid for *ctx* is used.

**SSL\_CTX\_get\_info\_callback**() returns a pointer to the currently set information callback function for *ctx*.

**SSL\_get\_info\_callback**() returns a pointer to the currently set information callback function for *ssl*.

When setting up a connection and during use, it is possible to obtain state information from the SSL/TLS engine. When set, an information callback function is called whenever the state changes, an alert appears, or an error occurs.

The callback function is called as **callback**(*SSL \*ssl*, *int where*, *int ret*). The *where* argument specifies information about where (in which context) the callback function was called. If *ret* is 0, an error condition occurred. If an alert is handled, SSL\_CB\_ALERT is set and *ret* specifies the alert information.

*where* is a bitmask made up of the following bits:

- SSL\_CB\_LOOP

  Callback has been called to indicate state change inside a loop.

- SSL\_CB\_EXIT

  Callback has been called to indicate error exit of a handshake function. (May be soft error with retry option for non-blocking setups.)

- SSL\_CB\_READ

  Callback has been called during read operation.

- SSL\_CB\_WRITE

  Callback has been called during write operation.

- SSL\_CB\_ALERT

  Callback has been called due to an alert being sent or received.

- SSL\_CB\_READ\_ALERT

  - SSL\_CB\_WRITE\_ALERT

  - SSL\_CB\_ACCEPT\_LOOP

  - SSL\_CB\_ACCEPT\_EXIT

  - SSL\_CB\_CONNECT\_LOOP

  - SSL\_CB\_CONNECT\_EXIT

  - SSL\_CB\_HANDSHAKE\_START

  Callback has been called because a new handshake is started.

- SSL\_CB\_HANDSHAKE\_DONE

  Callback has been called because a handshake is finished.

The current state information can be obtained using the SSL\_state\_string(3) family of functions.

The *ret* information can be evaluated using the SSL\_alert\_type\_string(3) family of functions.

## RETURN VALUES

**SSL\_CTX\_get\_info\_callback**() and **SSL\_get\_info\_callback**() return a pointer to the current callback or NULL if none is set.

## EXAMPLES

The following example callback function prints state strings, information about alerts being handled and error messages to the *bio\_err* *BIO*.

```
void
apps_ssl_info_callback(SSL *s, int where, int ret)
{
	const char *str;
	int w;
	w = where & ~SSL_ST_MASK;
	if (w & SSL_ST_CONNECT)
		str = "SSL_connect";
	else if (w & SSL_ST_ACCEPT)
		str = "SSL_accept";
	else
		str = "undefined";
	if (where & SSL_CB_LOOP) {
		BIO_printf(bio_err, "%s:%s\n", str,
		    SSL_state_string_long(s));
	} else if (where & SSL_CB_ALERT) {
		str = (where & SSL_CB_READ) ? "read" : "write";
		BIO_printf(bio_err, "SSL3 alert %s:%s:%s\n", str,
			SSL_alert_type_string_long(ret),
			SSL_alert_desc_string_long(ret));
	} else if (where & SSL_CB_EXIT) {
		if (ret == 0)
			BIO_printf(bio_err, "%s:failed in %s\n",
				str, SSL_state_string_long(s));
		else if (ret < 0) {
			BIO_printf(bio_err, "%s:error in %s\n",
				str, SSL_state_string_long(s));
		}
	}
}
```

## SEE ALSO

[ssl(3)](/ssl/3.md), SSL\_alert\_type\_string(3), SSL\_state\_string(3)

## HISTORY

These functions first appeared in SSLeay 0.6.0 and have been available since OpenBSD 2.4.