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.TH sasl_client_start "26 March 2000" SASL "SASL man pages"
.SH NAME
sasl_client_start \- Begin an authentication negotiation


.SH SYNOPSIS
.nf
.B #include <sasl.h>
.sp
.BI "int sasl_client_start(sasl_conn_t * " conn ", "
.BI "		      const char * " mechlist ", "
.BI "		      sasl_secret_t * " secret ", "
.BI "		      sasl_interact_t ** " prompt_need ", "
.BI "		      char ** " clientout ", "
.BI "		      unsigned * " clientoutlen ", "
.BI "		      const char ** " mech ");"

.fi
.SH DESCRIPTION

.B sasl_client_start()
selects a mechanism for authentication and starts the authentication
session. The mechlist is the list of mechanisms the client might like
to use. The mechanisms in the list are not necessarily supported by
the client or even valid. SASL determines which of these to use based
upon the security preferences specified earlier. The list of
mechanisms is typically a list of mechanisms the server supports
acquired from a capability request.

If SASL_INTERACT is returned the library needs some values to be
filled in before it can proceed. The prompt_need structure will be
filled in with requests. The application should fulfill these requests
and call sasl_client_start again with identical parameters (the
prompt_need parameter will be the same pointer as before but filled in
by the application).

.I mechlist
is a list of mechanisms the server has available. Punctuation if ignored.
.I secret
is the secret from a previous session. This parameter is optional. If SASL_INTERACT is returned 
.I prompt_need
is filled in with a list of prompts needed to continue. On sucess
.I clientout
and
.I clientoutlen
is created. It is the initial client response to send to the
server. This is allocated by the library and it is the job of the
client to send it over the network to the server and free it when it
is no longer needed. Any protocal specific encoding (such as base64
encoding) necessary needs to be done by the client. On sucess
.I mech
contains the name of the chosen SASL mechanism.

.PP

.SH "RETURN VALUE"

sasl_client_start returns an integer which corresponds to one of the
following codes. SASL_CONTINUE indicates sucess and that there are
more steps needed in the authentication. All other return codes
indicate errors and should either be handled or the authentication
session should be quit.


.SH ERRORS
.TP 0.8i
.B SASL_CONTINUE
Success. keep going.
.TP 0.8i
.B SASL_INTERACT
user interaction needed to fill in prompt_need list
.TP 0.8i
.B SASL_BADVERS
Mechanism version mismatch
.TP 0.8i
.B SASL_BADPARAM
error in config file
.TP 0.8i
.B SASL_NOMEM
not enough memory to complete operation

.SH "CONFORMING TO"
RFC 2222
.SH "SEE ALSO"
.BR other sasl stuff
.BR 
.BR