The value of $! is used in IO::Socket::SSL workflows to detect some error cases after I/O SSL operations. For example, in the _generic_read function the value of $! is used to distinguish between SSL EOF and more severe SSL errors.
The ossl_trace debug function is called automatically by the set_msg_callback system of OpenSSL before other perl code has a chance to check the value of $!. Unfortunately, this function is likely to corrupt the value of $! due to the call to Net::SSLeay::SSL_alert_desc_string_long (which sets $! to ENOENT when not found).
This can lead to annoying heisenbugs...
The value of
$!is used inIO::Socket::SSLworkflows to detect some error cases after I/O SSL operations. For example, in the_generic_readfunction the value of$!is used to distinguish between SSL EOF and more severe SSL errors.The
ossl_tracedebug function is called automatically by the set_msg_callback system of OpenSSL before other perl code has a chance to check the value of$!. Unfortunately, this function is likely to corrupt the value of$!due to the call toNet::SSLeay::SSL_alert_desc_string_long(which sets$!toENOENTwhen not found). This can lead to annoying heisenbugs...