---
name: "sasl_checkapop"
section: "3"
platform: "macos"
package: "passwordserver_sasl"
version: "215"
release: "macOS 26.5"
platforms: ["linux", "macos"]
url: "https://new.carta.tech/sasl_checkapop"
---

# sasl\_checkapop(3)

Check an APOP challenge/response

## NAME

sasl\_checkapop - Check an APOP challenge/response

## SYNOPSIS

```
#include <sasl/sasl.h>
int sasl_checkapop(sasl_conn_t *conn,
		       const char *challenge,
		       unsigned challen,
		       const char *response,
		       unsigned resplen);
```

## DESCRIPTION

**sasl\_checkapop()** will check an APOP challenge/response.  APOP is an optional POP3 (RFC 1939) authentication command which uses a shared secret (password). The password is stored in the SASL secrets database.  For information on the SASL shared secrets database see the *System Administrators Guide* in the doc/ directory of the SASL distribution.

If called with a **NULL** *challenge***,** **sasl\_checkapop()** will check to see if the APOP mechanism is enabled.

## RETURN VALUE

sasl\_checkapop returns an integer which corresponds to one of the following codes. SASL\_OK indicates that the authentication is complete. All other return codes indicate errors and should either be handled or the authentication session should be quit.  See [sasl\_errors(3)](/sasl_errors/3.md) for meanings of return codes.

## CONFORMING TO

RFC 4422, RFC 1939

## SEE ALSO

[sasl(3)](/sasl/3.md), [sasl\_errors(3)](/sasl_errors/3.md)