I've taken this script from documentation provided with php.

error_log function writes its first parameter to a file.

I've found that  all handlers works perfectly except destroy handler.

Here is the script:
--------------------------------------
<?
function open ($save_path, $session_name) {
  error_log (" started session \$save_path=$save_path, \$session_name=$session_name", 0);
  return(true);
}

function close() {
    error_log (" close session \$save_path=".session_save_path().", \$session_name=".session_name(), 0);
    return(true);
}

function read ($id) {
   error_log (" read session \$id=$id,\$save_path=".session_save_path().", \$session_name=".session_name(), 0);
	return true;
}

function write ($id, $sess_data) {
 error_log (" write session \$id=$id,\$sess_data=$sess_data,\$save_path=".session_save_path().", \$session_name=".session_name(), 0);
	return true;
}

function sess_destroy ($id) {
	error_log (" destroy session \$id=$id,\$sess_data=$sess_data,\$save_path=".session_save_path().", \$session_name=".session_name(), 0);
	return true;
}
function gc ($maxlifetime) {
  error_log (" gc session \$save_path=".session_save_path().", \$session_id=".session_id()." \$session_name=".session_name(), 0);
  return true;
}
session_set_save_handler ('open', 'close', 'read', 'write', 'sess_destroy', 'gc');
session_start();
?>
------------------------------------------------------


And here is a my php.ini (i have stripped all commented lines from it)

-------------------------------------------------------
[PHP]
engine = On
short_open_tag = On
asp_tags = Off
precision    =  14
y2k_compliance = Off
output_buffering = Off
output_handler =
zlib.output_compression = Off
implicit_flush = Off
allow_call_time_pass_reference = On
safe_mode = Off
safe_mode_exec_dir =
safe_mode_allowed_env_vars = PHP_
highlight.string  = #CC0000
highlight.comment = #FF9900
highlight.keyword = #006600
highlight.bg      = #FFFFFF
highlight.default = #0000CC
highlight.html    = #000000
expose_php = On

max_execution_time = 30     ; Maximum execution time of each script, in seconds
memory_limit = 8M      ; Maximum amount of memory a script may consume (8MB)

error_reporting  =  E_ALL & ~E_NOTICE
display_errors = On
log_errors = on
track_errors = On
error_prepend_string = "<font color=ff0000>"
error_append_string = "</font>"
error_log = c:\php_test.txt
warn_plus_overloading = Off

variables_order = "EGPCS"
register_globals = On
register_argc_argv = On
post_max_size = 8M
gpc_order = "GPC"

magic_quotes_gpc = On
magic_quotes_runtime = Off    
magic_quotes_sybase = Off
auto_prepend_file =
auto_append_file =
default_mimetype = "text/html"

doc_root =
user_dir =
extension_dir = "c:\program files\php\extensions"

enable_dl = On

file_uploads = On
upload_max_filesize = 2M

allow_url_fopen = On
extension="php_printer.dll"
extension="php_webmail.dll"

[Syslog]
define_syslog_variables  = On

[mail function]
SMTP = 192.165.0.1
sendmail_from = me@localhost.com


[SQL]
sql.safe_mode = Off

odbc.allow_persistent = On
odbc.check_persistent = On
odbc.max_persistent = -1
odbc.max_links = -1  
odbc.defaultlrl = 4096  
odbc.defaultbinmode = 1  

[MySQL]
mysql.allow_persistent = On
mysql.max_persistent = -1
mysql.max_links = -1
mysql.default_port =
mysql.default_socket =
mysql.default_host =
mysql.default_user =
mysql.default_password =

[bcmath]
bcmath.scale = 0

[Session]
; Handler used to store/retrieve data.
session.save_handler = user
session.save_path = C:\\temp
session.use_cookies = 1
session.name = PHPSESSID
session.auto_start = 0
session.cookie_lifetime = 0
session.cookie_path = /
session.cookie_domain =
session.serialize_handler = php
session.gc_probability = 1
session.gc_maxlifetime = 3
session.referer_check =
session.entropy_length = 0
session.entropy_file =
session.cache_limiter = nocache
session.cache_expire = 1
session.use_trans_sid = 1
url_rewriter.tags = "a=href,area=href,frame=src,input=src,form=fakeentry"
[Sockets]
sockets.use_system_read = On
------------------------------------------------------

Thank you.
Alex.