Migrating to version 4

A guide to help developers port their code from libical v3.x to libical 4.0.

CMake options

Some CMake option names have been removed or renamed (deprecated) to the LIBICAL namespace.

Please change your build scripts to use the new names before the next major release.

User-specific:

Old Name	New Name
ICAL_ALLOW_EMPTY_PROPERTIES	removed
ICAL_BUILD_DOCS	LIBICAL_BUILD_DOCS
ICAL_ERRORS_ARE_FATAL	removed
ICAL_GLIB	LIBICAL_GLIB
ICAL_GLIB_VAPI	LIBICAL_GLIB_VAPI
ICAL_GLIB_BUILD_DOCS	LIBICAL_GLIB_BUILD_DOCS
USE_BUILTIN_TZDATA	LIBICAL_ENABLE_BUILTIN_TZDATA
USE_32BIT_TIME_T	LIBICAL_ENABLE_MSVC_32BIT_TIME_T
GOBJECT_INTROSPECTION	LIBICAL_GOBJECT_INTROSPECTION
WITH_CXX_BINDINGS	LIBICAL_CXX_BINDINGS
ENABLE_LTO_BUILD	CMAKE_INTERPROCEDURAL_OPTIMIZATION
SHARED_ONLY	removed
STATIC_ONLY	LIBICAL_STATIC

Developer-specific:

Old Name	New Name
ABI_DUMPER	LIBICAL_DEVMODE_ABI_DUMPER
ADDRESS_SANITIZER	LIBICAL_DEVMODE_ADDRESS_SANITIZER
LIBICAL_SYNCMODE_THREADLOCAL	LIBICAL_DEVMODE_SYNCMODE_THREADLOCAL
THREAD_SANITIZER	LIBICAL_DEVMODE_THREAD_SANITIZER
UNDEFINED_SANITIZER	LIBICAL_DEVMODE_UNDEFINED_SANITIZER

Conditional compilation

To continue supporting the 3.0 version you can use conditional compilation, like so:

#if ICAL_CHECK_VERSION(4,0,0)
<...new code for the libical 4.0 version ...>
#else
<...old code for the libical 3.0 version ...>
#endif

you can handle code that no longer exists in 4.0 with:

#if !ICAL_CHECK_VERSION(4,0,0)
<...old code for the libical 3.0 version ...>
#endif

ICAL_ENABLE_ERRORS_ARE_FATAL

The ICAL_ENABLE_ERRORS_ARE_FATAL conditional compile macro and accompanying CMake option ICAL_ENABLE_ERRORS_ARE_FATAL are removed.

To abort whenever an error is encountered use the icalerror_set_errors_are_fatal() and icalerror_get_errors_are_fatal() functions.

ICAL_ALLOW_EMPTY_PROPERTIES

The ICAL_ALLOW_EMPTY_PROPERTIES conditional compile macro and accompanying CMake option ICAL_ALLOW_EMPTY_PROPERTIES are removed.

To allow empty properties you can use the new runtime functions icalproperty_set_allow_empty_properties() and icalproperty_get_allow_empty_properties().

PVL_USE_MACROS

The PVL_USE_MACROS conditional compile macro is removed. The pvl unit always compiles the pvl_data function.

ICAL_SETERROR_ISFUNC

The ICAL_SETERROR_ISFUNC conditional compile macro is removed. The icalerror unit always compiles the icalerror_set_errno function.

ICAL_BOOLEAN_TRUE and ICAL_BOOLEAN_FALSE

The ICAL_BOOLEAN_TRUE and ICAL_BOOLEAN_FALSE macros are removed. The C library is C99 standards compliant and uses bool types.

C library

Modified functions

• icalrecurrencetype_from_string() was replaced by icalrecurrencetype_new_from_string(), which returns a struct icalrecurrencetype * rather than a struct icalrecurrencetype. Free the allocated memory using icalrecurrencetype_unref().
• The following functions now take arguments of type struct icalrecurrencetype * rather than struct icalrecurrencetype:
  • icalproperty_new_rrule()
  • icalproperty_get_rrule()
  • icalproperty_set_rrule()
  • icalproperty_vanew_rrule()
  • icalproperty_new_exrule()
  • icalproperty_set_exrule()
  • icalproperty_get_exrule()
  • icalproperty_vanew_exrule()
  • icalrecur_iterator_new()
  • icalvalue_new_recur()
  • icalvalue_set_recur()
  • icalvalue_get_recur()
• The following functions now return a value of type struct icalrecurrencetype * rather than struct icalrecurrencetype:
  • icalproperty_get_rrule()
  • icalproperty_get_exrule()
  • icalvalue_get_recur()
• icaltimezone_convert_time() now populates the icaltimetype zone member on conversion; i.e. the timezone information is not lost during a conversion.
• To more clearly illustrate their intended purpose, the icaldurationtype_from_int() and icaldurationtype_as_int() have been renamed to icaldurationtype_from_seconds() and icaldurationtype_as_seconds(), respectively. The functionality of icaldurationtype_from_seconds has not changed. The functionality for icaldurationtype_as_seconds has changed, such that a duration with days or weeks fails with a ICAL_MALFORMEDDATA_ERROR and returns 0. To preserve the former logic of icaldurationtype_as_int, use he newly introduced icaldurationtype_as_utc_seconds.
• Similarly, the icaltime_add() and icaltime_subtract() functions are now called icalduration_extend() and icalduration_from_times(). Their functionality has not changed.
• The get_zone_directory() and set_zone_directory() functions are have been renamed to icaltimezone_get_zone_directory() and icaltimezone_set_zone_directory(), respectively.
• The icaltzutil_set_zone_directory() and icaltzutil_get_zone_directory() functions are now called icaltimezone_set_system_zone_directory() and icaltimezone_get_system_zone_directory() respectively.
• In previous versions, the icalvalue_compare() function returned 0 if unknown or null value types were encountered; in this version, ICAL_XLICCOMPARETYPE_NONE is returned instead.
• In previous versions, the icalcomponent_get_status() returned 0 if a problem parsing the status property was detected; in this version, ICAL_STATUS_NONE is returned instead.
• The ical_bt() and icalerrno_return() functions have been renamed to icalerror_backtrace() and icalerror_icalerrno()` respectively for the sake of consistent function name-spacing.

New functions

The following functions have been added:

• icallimit_set()
• icallimit_get()
• icalarray_set_element_at()
• icalrecurrencetype_new()
• icalrecurrencetype_ref()
• icalrecurrencetype_unref()
• icalrecurrencetype_clone()
• icalrecurrencetype_encode_day()
• icalrecurrencetype_encode_month()
• icalcomponent_clone()
• icalproperty_clone()
• icalproperty_set_allow_empty_properties()
• icalproperty_get_allow_empty_properties()
• icalparameter_clone()
• icalparameter_kind_value_kind()
• icalparameter_is_multivalued()
• icalparameter_decode_value()
• icalvalue_clone()
• icalcluster_clone()
• icalrecur_iterator_prev()
• icalrecur_resize_by()
• icalrecurrencetype_new()
• icalrecurrencetype_ref()
• icalrecurrencetype_unref()
• icalrecurrencetype_clone()
• icalrecurrencetype_from_string()
• icalcomponent_new_iana()
• icalcomponent_set_iana_name()
• icalcomponent_get_iana_name()
• icalcomponent_set_x_name()
• icalcomponent_get_x_name()
• icalcomponent_get_component_name()
• icalcomponent_get_component_name_r()
• ical_set_invalid_rrule_handling_setting()
• ical_get_invalid_rrule_handling_setting()
• icalparser_get_ctrl()
• icalparser_set_ctrl()
• icaltimezone_tzid_prefix()
• icaltimezone_set_system_zone_directory()
• icalcompiter_is_valid()
• icalpropiter_is_valid()
• icalproperty_new_iana()
• icalproperty_set_iana_name()
• icalproperty_get_iana_name()
• and the new functions for the icalstrarray and icalenumarray data types

Removed functions

• icalmime_parse() has been removed. Please use another library if you need a MIME parser.
• icaltime_week_number() has been removed. (it never properly accounted for the start day of the week in different locales).
• icalrecurrencetype_clear() has been removed.
• icaltimezone_release_zone_tab() has been removed. Use `icaltimezone_free_builtin_timezones() instead.
• icalrecurrencetype_rscale_is_supported() has been removed as RSCALE=GREGORIAN is supported without libicu now. Replace icalrecurrencetype_rscale_is_supported() calls with a true condition.
• These deprecated functions have been removed:
  • caldat()
  • juldat()
  • icalcomponent_new_clone()
  • icalparameter_new_clone()
  • icalproperty_new_clone()
  • icalvalue_new_clone()
  • icalcluster_new_clone()
• No longer publicly visible functions:
  • icaltzutil_fetch_timezone()
  • icalrecurrencetype_clear()
  • icalproperty_new_impl()
  • icaltimezone_array_new()
  • icaltimezone_array_append_from_vtimezone()
  • icaltimezone_array_free()

Removed macros

These convenience macros were added in version 3 to ease porting from older versions. They have been removed in version 4 and should be replaced with their actual function names as follows:

Old Macro Name	Actual Function Name
icalenum_action_to_string	icalproperty_action_to_string
icalenum_class_to_string	icalproperty_class_to_string
icalenum_component_kind_to_string	icalcomponent_kind_to_string
icalenum_method_to_string	icalproperty_method_to_string
icalenum_participanttype_to_string	icalproperty_participanttype_to_string
icalenum_property_kind_to_string	icalproperty_kind_to_string
icalenum_property_kind_to_value_kind	icalproperty_kind_to_value_kind
icalenum_resourcetype_to_string	icalproperty_resourcetype_to_string
icalenum_status_to_string	icalproperty_status_to_string
icalenum_string_to_action	icalproperty_string_to_action
icalenum_string_to_class	icalproperty_string_to_class
icalenum_string_to_component_kind	icalcomponent_string_to_kind
icalenum_string_to_method	icalproperty_string_to_method
icalenum_string_to_participanttype	icalproperty_string_to_participanttype
icalenum_string_to_property_kind	icalproperty_string_to_kind
icalenum_string_to_resourcetype	icalproperty_string_to_resourcetype
icalenum_string_to_status	icalproperty_string_to_status
icalenum_string_to_transp	icalproperty_string_to_transp
icalenum_string_to_value_kind	icalvalue_string_to_kind
icalenum_transp_to_string	icalproperty_transp_to_string
icalenum_value_kind_to_string	icalvalue_kind_to_string

Added data types

• These data types have been added:
  • icalstrarray - for manipulating an array of strings
  • icalenumarray_element - structure to hold a generic enum value
  • icalenumarray - for manipulating an array of enum elements

Removed data types

• These data structures have been removed (as they were never used):
  • struct icaltimezonetype
  • struct icaltimezonephase

Migrating from 3.0 to 4.0

const pointers

Many function signatures have been changed to use const pointers.

bool return values

A number of function signatures have been changed to use 'bool' rather than 'int' types.

This is implemented using the C99 standards compliant <stdbool.h> header.

Clone functions

Replace all ical*_new_clone() function calls with ical*_clone() . ie, use icalcomponent_clone() rather then icalcomponent_new_clone().

icalrecurrencetype now passed by reference

The way struct icalrecurrencetype is passed between functions has been changed. While it was usually passed by value in 3.0, it is now passed by reference. A reference counting mechanism is applied that takes care of de-allocating an instance as soon as the reference counter goes to 0.

Code like this in libical 3.0:

struct icalrecurrencetype recur;
 
icalrecurrencetype_clear(&recur);
 
// Work with the object

changes to this in libical 4.0:

struct icalrecurrencetype *recur;
 
// allocate
recur = icalrecurrencetype_new();
if (recur) {
 
    // Work with the object
 
    // deallocate
    icalrecurrencetype_unref(recur);
} else {
    // out of memory error handling
}

icalgeotype now uses character strings rather than doubles

The members of struct icalgeotype for latitude ('lat) and longitude ('lon) have been changed to use ICAL_GEO_LEN long character strings rather than the double type.

This means that simple assignments in 3.0 must be replaced by string copies.

geo.lat = 0.0;
geo.lon = 10.0;

becomes

strncpy(geo.lat, "0.0", ICAL_GEO_LEN-1);
strncpy(geo.lon, "10.0", ICAL_GEO_LEN-1);

and

double lat = geo.lat;
double lon = geo.lon;

becomes

double lat, lon;
sscanf(geo.lat, "%lf", &lat);
sscanf(geo.lon, "%lf", &lon);

icaltime_adjust

The icaltime_adjust function no longer adjusts null icaltimetypes.

Working with icalvalue and icalproperty

Code like this in libical 3.0:

icalvalue *recur_value = ...;
struct icalrecurrencetype recur = icalvalue_get_recur(recur_value);
 
// Work with the object

changes to this in libical 4.0:

icalvalue *recur_value = ...;
struct icalrecurrencetype *recur = icalvalue_get_recur(recur_value);
 
// Work with the object
// No need to unref

Multi-valued parameters

Support for these multi-valued parameters is added in libical 4.0.

• DELEGATED-FROM (RFC 5545)
• DELEGATED-TO (RFC 5545)
• MEMBER (RFC 5545)
• DISPLAY (RFC 7986)
• FEATURE (RFC 7986)

You can access the 'nth' value for such parameters using the new "_nth" functions.

For example, to access the first delegated-to attendee use

param = icalproperty_get_first_parameter(prop, ICAL_DELEGATEDTO_PARAMETER);
icalparameter_get_delegatedto_nth(param, 0)

Setting the tzid

The icaltimezone_set_tzid_prefix function now allows setting an empty prefix. In older libical versions, calling icaltimezone_set_tzid_prefix with an empty tzid prefix would reset to the BUILTIN_TZID_PREFIX value (i.e. ""/freeassociation.sourceforge.net/").

The new publicly visible function icaltimezone_tzid_prefix returns the current tzid prefix string.

Note that the tzid prefix must be globally unique (such as a domain name owned by the developer of the calling application), and begin and end with forward slashes. The tzid string must be fewer than 256 characters long.

C++ library

Modified methods

• The following methods now take arguments of type struct icalrecurrencetype * rather than const struct icalrecurrencetype &:
  • ICalValue.set_recur()
  • ICalProperty.set_exrule()
  • ICalProperty.set_rrule()
• The following methods now returns a value of type struct icalrecurrencetype * rather than struct icalrecurrencetype:
  • ICalValue.get_recur()
  • ICalProperty.get_exrule()
  • ICalProperty.get_rrule()

icalrecurrencetype.by_xxx static arrays replaced by dynamically allocated ones

I.e. memory short by_hour[ICAL_BY_DAY_SIZE] etc. are replaced by

typedef struct
{
  short *data;
  short size;
} icalrecurrence_by_data;
 
struct icalrecurrencetype {
  ...
  icalrecurrence_by_data by[ICAL_BY_NUM_PARTS];
}

Memory is allocated in the required size using the new icalrecur_resize_by() function. It is automatically freed together with the containing icalrecurrencetype. As the size of the array is stored explicitly, no termination of the array with special value ICAL_RECURRENCE_ARRAY_MAX is required anymore. The array is iterated by comparing the iterator to the size member value.

Migrating icalrecurrencetype.by_xxx static arrays usage from 3.0 to 4.0

Code like this in libical 3.0:

icalrecurrencetype recur;
...
recur.by_hour[0] = 12;
recur.by_hour[1] = ICAL_RECURRENCE_ARRAY_MAX;

changes to something like this in libical 4.0:

icalrecurrencetype *recur;
...
if (!icalrecur_resize_by(&recur->by[ICAL_BY_HOUR], 1)) {
  // allocation failed
  // error handling
} else {
  recur.by[ICAL_BY_HOUR].data[0] = 12;
}

GLib/Python bindings - changed ICalGLib.Recurrence.*_by_* methods

i_cal_recurrence_*_by_xxx* methods have been replaced by more generic versions that take the 'by' type (day, month, ...) as a parameter.

i_cal_bt and i_cal_errno_return are renamed to i_calerror_backtrace and i_cal_errno_return, respectively.

Migrating ICalGLib.Recurrence.*_by_* methods from 3.0 to 4.0

Code like this in libical 3.0:

recurrence.set_by_second(0,
recurrence.get_by_second(0) + 1)

changes to something like this in libical 4.0:

recurrence.set_by(ICalGLib.RecurrenceByRule.BY_SECOND, 0,
recurrence.get_by(ICalGLib.RecurrenceByRule.BY_SECOND, 0) + 1)