I used this script to test, php-xdebug extension is mentionned in phpinfo(), but it's not called in var_dump and undefined_const error call.
<?php
error_reporting(E_ALL);
var_dump(PHP_VERSION);
var_dump(array('toto'=>23, array('toto')));
undefined_const;
phpinfo();
My xdebug config file :
; zend_extension_ts=/usr/lib/php/extensions/xdebug.so
zend_extension=/usr/lib/php/extensions/xdebug.so
[xdebug]
; When this setting is set to on, the tracing of function calls will be
; enabled just before the script is run. This makes it possible to trace
; code in the auto_prepend_file.
xdebug.auto_trace = 0
; This setting, defaulting to On, controls whether Xdebug should write the
; filename used in include(), include_once(), require() or require_once()
; to the trace files.
xdebug.collect_includes = 1
; This setting, defaulting to 0, controls whether Xdebug should collect the
; parameters passed to functions when a function call is recorded in either the
; function trace or the stack trace.
;
; The setting defaults to Off because for very large scripts it may use huge
; amounts of memory and therefore make it impossible for the huge script to
; run. You can most safely turn this setting on, but you can expect some
; problems in scripts with a lot of function calls and/or huge data structures
; as parameters. Xdebug 2 will not have this problem with increased memory
; usage, as it will never store this information in memory. Instead it will
; only be written to disk. This means that you need to have a look at the disk
; usage though.
;
; This setting can have four different values. For each of the values a
; different amount of information is shown. Below you will see what information
; each of the values provides. See also the introduction of the feature Stack
; Traces for a few screenshots.
;
; Value Argument Information Shown
; 0 None.
; 1 Type and number of elements (f.e. string(6), array(8)).
; 2 Type and number of elements, with a tool tip for the full information
; ().
; 3 Full variable contents (with the limits respected as set by
; xdebug.var_display_max_children, xdebug.var_display_max_data and
; xdebug.var_display_max_depth.
; 4 Full variable contents and variable name.
; () in the CLI version of PHP it will not have the tool tip, nor in output
; files.
xdebug.collect_params = 0
; This setting, defaulting to Off, controls whether Xdebug should write the
; return value of function calls to the trace files
xdebug.collect_return = 0
; This setting tells Xdebug to gather information about which variables are
; used in a certain scope. This analysis can be quite slow as Xdebug has to
; reverse engineer PHP's opcode arrays. This setting will not record which
; values the different variables have, for that use xdebug.collect_params.
; This setting needs to be enabled only if you wish to use
; xdebug_get_declared_vars().
xdebug.collect_vars = off
; If this setting is On then stacktraces will be shown by default on an error
; event. You can disable showing stacktraces from your code with
; xdebug_disable(). As this is one of the basic functions of Xdebug, it is
; advisable to leave this setting set to 'On'.
xdebug.default_enable = on
; Controls whether the values of the superglobals as defined by the
; xdebug.dump.* settings whould be shown or not.
xdebug.dump_globals = 1
; Controls whether the values of the superglobals should be dumped on all error
; situations (set to Off) or only on the first (set to On).
xdebug.dump_once = 1
; If you want to dump undefined values from the superglobals you should set this
; setting to On, otherwise leave it set to Off.
xdebug.dump_undefined = 0
; Controls whether Xdebug should enforce 'extended_info' mode for the PHP
; parser; this allows Xdebug to do file/line breakpoints with the remote
; debugger. When tracing or profiling scripts you generally want to turn off
; this option as PHP's generated oparrays will increase with about a third of
; the size slowing down your scripts. This setting can not be set in your
; scripts with ini_set(), but only in php.ini.
xdebug.extended_info = 1
; Controls which IDE Key Xdebug should pass on to the DBGp debugger handler.
; The default is based on environment settings. First the environment setting
; DBGP_IDEKEY is consulted, then USER and as last USERNAME. The default is set
; to the first environment variable that is found. If none could be found the
; setting has as default ''.
xdebug.idekey = ''
; This is the base url for the links from the function traces and error message
; to the manual pages of the function from the message. It is advisable to set
; this setting to use the closest mirror.
xdebug.manual_url = 'http://www.php.net'
; Controls the protection mechanism for infinite recursion protection. The
; value of this setting is the maximum level of nested functions that are
; allowed before the script will be aborted.
xdebug.max_nesting_level = 100
; When this setting is set to 1, profiler files will not be overwritten when a
; new request would map to the same file (depnding on the
; xdebug.profiler_output_name setting. Instead the file will be appended to
; with the new profile.
xdebug.profiler_append = 0
; Enables Xdebug's profiler which creates files in the profile output
; directory. Those files can be read by KCacheGrind to visualize your data.
; This setting can not be set in your script with ini_set().
xdebug.profiler_enable = 0
; When this setting is set to 1, you can trigger the generation of profiler
; files by using the XDEBUG_PROFILE GET/POST parameter, or send a cookie with
; the name XDEBUG_PROFILE. This will then write the profiler data to defined
; directory.
xdebug.profiler_enable_trigger = 0
; The directory where the profiler output will be written to, make sure that
; the user who the PHP will be running as has write permissions to that
; directory. This setting can not be set in your script with ini_set().
xdebug.profiler_output_dir = /tmp
; This setting determines the name of the file that is used to dump traces
; into. The setting specifies the format with format specifiers, very similar
; to sprintf() and strftime(). There are several format specifiers that can be
; used to format the file name.
xdebug.profiler_output_name = 'cachegrind.out.%p'
; Normally you need to use a specific HTTP GET/POST variable to start remote
; debugging (see Remote Debugging). When this setting is set to 'On' Xdebug
; will always attempt to start a remote debugging session and try to connect
; to a client, even if the GET/POST/COOKIE variable was not present.
xdebug.remote_autostart = 0
; This switch controls whether Xdebug should try to contact a debug client
; which is listening on the host and port as set with the settings
; xdebug.remote_host and xdebug.remote_port. If a connection can not be
; established the script will just continue as if this setting was Off.
xdebug.remote_enable = 0
; Can be either 'php3' which selects the old PHP 3 style debugger output,
; 'gdb' which enables the GDB like debugger interface or 'dbgp' - the brand
; new debugger protocol. The DBGp protocol is more widely supported by clients.
; See more information in the introduction for Remote Debugging.
xdebug.remote_handler = 'gdb'
; Selects the host where the debug client is running, you can either use a
; host name or an IP address.
xdebug.remote_host = 'localhost'
; If set to a value, it is used as filename to a file to which all remote
; debugger communications are logged. The file is always opened in
; append-mode, and will therefore not be overwritten by default. There is no
; concurrency protection available.
xdebug.remote_log = ''
; Selects when a debug connection is initiated. This setting can have two
; different values:
; - req, Xdebug will try to connect to the debug client as soon as the script
; starts.
; - jit, Xdebug will only try to connect to the debug client as soon as an
; error condition occurs.
xdebug.remote_mode = 'req'
; The port to which Xdebug tries to connect on the remote host. Port 9000 is
; the default for both the client and the bundled debugclient. As many clients
; use this port number, it is best to leave this setting unchanged.
xdebug.remote_port = 9000
; When this setting is set to 1, Xdebug will show a stack trace whenever an
; exception is raised - even if this exception is actually caught.
xdebug.show_exception_trace = 0
; When this setting is set to something != 0 Xdebug's generated stack dumps in
; error situations will also show all variables in the top-most scope. Beware
; that this might generate a lot of information, and is therefore turned off
; by default.
xdebug.show_local_vars = 0
; When this setting is set to something != 0 Xdebug's human-readable generated
; trace files will show the difference in memory usage between function calls.
; If Xdebug is configured to generate computer-readable trace files then they
; will always show this information.
xdebug.show_mem_delta = 0
; The format of the trace file.
;
; Value Description
; 0 shows a human readable indented trace file with: time index, memory
; usage, memory delta (if the setting xdebug.show_mem_delta is enabled),
; level, function name, function parameters (if the setting
; xdebug.collect_params is enabled, filename and line number.
; 1 writes a computer readable format which has two different records.
; There are different records for entering a stack frame, and leaving
; a stack frame. The table below lists the fields in each type of record.
; Fields are tab separated.
;
; See http://xdebug.org/docs/all_settings#trace_format for complete
; introduction
xdebug.trace_format = 0
; When set to '1' the trace files will be appended to, instead of being
; overwritten in subsequent requests.
xdebug.trace_options = 0
; The directory where the tracing files will be written to, make sure that the
; user who the PHP will be running as has write permissions to that directory.
xdebug.trace_output_dir = '/tmp'
; This setting determines the name of the file that is used to dump traces
; into. The setting specifies the format with format specifiers, very similar
; to sprintf() and strftime(). There are several format specifiers that can be
; used to format the file name. The '.xt' extension is always added
; automatically.
;
; See http://xdebug.org/docs/all_settings#trace_output_name for complete
; introduction
xdebug.trace_output_name = 'trace.%c'
; Controls the amount of array children and object's properties are shown when
; variables are displayed with either xdebug_var_dump(),
; xdebug.show_local_vars
; or through Function Traces. This setting does not have any influence on the
; number of children that is send to the client through the Remote Debugging
; feature.
xdebug.var_display_max_children = 128
; Controls the maximum string length that is shown when variables are
; displayed with either xdebug_var_dump(), xdebug.show_local_vars or through
; Function Traces. This setting does not have any influence on the amount of
; data that is send to the client through the Remote Debugging feature.
xdebug.var_display_max_data = 512
; Controls how many nested levels of array elements and object properties are
; when variables are displayed with either xdebug_var_dump(),
; xdebug.show_local_vars or through Function Traces. This setting does not
; have any influence on the depth of children that is send to the client
; through the Remote Debugging feature.
xdebug.var_display_max_depth = 3 | 