7 * Libucw finally has a clean ABI, which does not pollute namespace, risking
8 collisions with other libraries. However, we did not want to abandon our
9 nicely and simply named functions, so the header files define macros,
10 which translate names of all externally visible symbols to start with `ucw_`.
11 If you don't like this, configure libucw with `CONFIG_UCW_CLEAN_ABI` turned off.
12 * All helper utilities are now installed with names starting with `ucw-` to
14 * The auxiliary libraries have been renamed to `libucw-charset`, `libucw-images`,
16 * A <<opt:,parser of command-line options>> has been added, similar in spirit to
17 our <<conf:,configuration file parser>>. The <<conf:getopt_h,getopt>> module
19 * `<stdbool.h>` is automatically included by `<ucw/lib.h>`.
20 * *Incompatible:* The interface of the <<heap:,heap>> module was cleaned up
21 to remove non-systematic side-effects. The `HEAP_INSERT` operation is now
22 a proper insert (previously, it was just cleanup after insertion performed
23 by the caller), similarly `HEAP_INCREASE` and `HEAP_DECREASE`. The `HEAP_DELMIN`
24 operation was renamed to `HEAP_DELETE_MIN`. New operations `HEAP_REPLACE` and
25 `HEAP_REPLACE_MIN` have been added. If you need to track positions of elements
26 in the heap, please check the notes at individual functions.
27 * The <<conf:,configuration file parser>> has been improved:
28 ** Multiple instances of the configuration parser are supported.
29 ** *Incompatible:* As there may be more instances, we can no longer use
30 global variables to control the configuration system. In particular,
31 `cf_need_journal` and `cf_pool` variables have been replaced by
32 functions <<conf:fun_cf_set_journalling,`cf_set_journalling()`>> and
33 <<conf:fun_cf_get_pool,`cf_get_pool()`>>.
34 ** *Incompatible:* Loading of configuration files has been decoupled from
35 the getopt wrapper, so you might need to include `conf.h` for functions
36 which were previously declared in `getopt.h`.
37 ** New functions have been added:
38 <<conf:fun_cf_open_group,`cf_open_group()`>>,
39 <<conf:fun_cf_close_group,`cf_close_group()`>>, and
40 <<conf:fun_cf_revert,`cf_revert()`>>.
41 * <<daemon:,Daemon helpers>> have been added including a new `daemon-control`
42 utility. The old `daemon-helper` utility has been obsoleted and it is not
44 * <<signal:,Signal helpers>> for translation between signal names and numbers
46 * The fastbuf I/O layer received a new back-end <<fastbuf:fbmulti,fb_multi>>,
47 which concatenates several fastbuf streams to form a single virtual stream.
48 * *Incompatible* The `UCW::CGI` Perl module has its custom error handlers
49 (which override default Perl error handlers) split off to a separate module
50 `UCW::CGI::ErrorHandler`.
51 * Added <<varint:,varint>> module for efficient UTF-8-like encoding of 64-bit
52 integers to byte sequences.
57 * *Incompatible:* The `timestamp_t` type has been decoupled from wall clock time.
58 It now specifies the number of milliseconds from an unspecified origin, so that
59 it can for example refer to the system monotonic clock. The `ucw_time_t` type
62 * The <<mainloop:,mainloop>> module has been rewritten:
63 ** Multiple instances of the main loop are supported (to be used in different
64 threads or locally within a library function).
65 ** The new implementation is more efficient: it uses heaps for timers,
66 epoll() for file descriptors (when available).
67 ** The return value of <<mainloop:struct_main_file,`main_file`>> handlers has been
68 changed to <<mainloop:enum_main_hook_return,`HOOK_IDLE`>> and <<mainloop:enum_main_hook_return,`HOOK_RETRY`>>.
69 However, the numerical values are equal, so old code should keep working.
70 ** *Incompatible:* The main loop time (`main_now`) has been decoupled from wall clock time
71 and moved to a field in the `main_context` structure. It can be accessed either directly
72 or via <<mainloop:fun_main_get_now,`main_get_now()`>>. The `main_now_seconds` variable has
73 been removed, `main_idle_time` has become a structure field.
74 ** *Incompatible:* The interface for asynchronous reading and writing
75 (file_read() and friends) has been separated from the core of the main loop.
76 Use <<mainloop:struct_main_block_io,`struct main_block_io`>> and related functions instead.
77 ** *Incompatible:* file_close_all() is gone. You have to call <<mainloop:fun_main_teardown,`main_teardown()`>>
78 or <<mainloop:fun_main_destroy,`main_destroy()`>> to clean up properly after fork().
79 ** Added support for <<mainloop:signal,synchronous delivery of signals>>.
80 ** Added relative timers: <<mainloop:fun_timer_add_rel,`timer_add_rel()`>>.
81 ** Modification of events from a running event handler is always safe.
82 ** Deleting an already deleted event is always safe.
83 ** For any event type, it is possible to ask whether it is active (added to the mainloop) or not: <<mainloop:fun_hook_is_active,`hook_is_active()`>> and friends.
84 ** A new mainloop front-end for asynchronous <<mainloop:recordio,record-based I/O>> has been added.
86 * Added support for <<trans:,resource pools and transactions>>, which is a general
87 mechanism for tracking resources and reporting errors. It is still considered
88 experimental, so the API can change in future releases.
90 * Added a growing array module `gary.h`, similar to `gbuf.h`, but with
91 a much more convenient interface.
93 * The <<lists:,Circular linked lists>> can recognize unlinked nodes,
94 see <<lists:fun_clist_unlink,`clist_unlink()`>>.
96 * Added `strtonum.h` -- a module for precise parsing of numbers.
98 * When compiled by a recent enough GCC, `__thread` is used for thread-local variables,
99 which is more efficient than the POSIX per-thread storage.
100 ** *Incompatible:* `ucwlib_context->thread_id` is no longer available directly,
101 please use ucwlib_thread_id() instead.
103 * *Incompatible:* Several modules have been declared obsolete and removed:
104 ** `sighandler` -- generic signal handling (it still exists internally)
105 ** `qache` -- a mmap-based shared cache
106 ** `prefetch` -- an interface to memory prefetch instructions; superseded by GCC `__builtin_prefetch`
107 ** `randomkey` -- a generator of cryptographically strong pseudo-random tokens; will be replaced
108 by something more generic soon
109 ** `profile` -- a profiling hack
111 * *Incompatible:* Several modules now have their own header files:
112 ** `process.h` -- all functions related to processes, previously declared in `lib.h`
113 ** `io.h` -- functions related to files from `lib.h` and `lfs.h`
114 ** `time.h` -- timestamps and interval timers, previously in `lib.h`
116 * *Incompatible:* Several configuration options were renamed or removed:
117 ** `CONFIG_FAKE_ELTPOOL` → `CONFIG_UCW_FAKE_ELTPOOL`
118 ** `CONFIG_LARGE_FILES` → `CONFIG_UCW_LARGE_FILES`
119 ** `CONFIG_OWN_GETOPT` → `CONFIG_UCW_OWN_GETOPT`
120 ** `CONFIG_DIRECT_IO` → `CONFIG_UCW_DIRECT_IO`
121 ** `DEFAULT_CONFIG` → `CONFIG_UCW_DEFAULT_CONFIG`
122 ** `ENV_VAR_CONFIG` → `CONFIG_UCW_ENV_VAR_CONFIG`
123 ** `CONFIG_LFS` was removed
124 ** `CONFIG_URL_ESCAPE_COMPAT` was removed
126 * `UCW::Configure` supports running of test programs.
128 * `UCW::CGI` support multiple argument tables and UTF-8 mode. Also, it uses the
129 proper HTTP status codes when reporting errors.
131 * Implementation details of <<fastbuf:,fastbufs>> have changed. The new code checks
132 invariants more carefully, so it is possible that custom fastbuf back-ends which
133 are buggy now fail, although they previously seemed to work.
138 This was the first stand-alone release of LibUCW. Before that, LibUCW was developed
139 as a part of the http://www.ucw.cz/holmes/[Sherlock Holmes project].