1 2 3 GLib's configure options and corresponding macros 4 ================================================= 5 6 --enable-debug=no 7 -DG_DISABLE_ASSERT -DG_DISABLE_CHECKS 8 --enable-debug=minimum [default for stable branches] 9 none 10 --enable-debug=yes [default for development branches] 11 -DG_ENABLE_DEBUG -g 12 --enable-gc-friendly=yes 13 #define ENABLE_GC_FRIENDLY_DEFAULT 1 14 --disable-mem-pools=yes 15 #define DISABLE_MEM_POOLS 1 16 17 Besides these, there are some local feature specific options, but my main 18 focus here is to concentrate on macros that affect overall GLib behaviour 19 and/or third party code. 20 21 22 Notes on GLib's internal and global macros 23 ========================================== 24 25 26 ENABLE_GC_FRIENDLY_DEFAULT 27 Newly allocated memory that isn't directly initialized, as well 28 as memory being freed should be reset to 0. The point here is to 29 allow memory checkers and similar programs that use bohem GC alike 30 algorithms to produce more accurate results. 31 This can also be accomplished by setting the environment variable 32 G_DEBUG=gc-friendly. 33 DISABLE_MEM_POOLS 34 Many small chunks of memory are often allocated via collective pools 35 in GLib and are cached after release to speed up reallocations. 36 For sparse memory systems this behaviour is often inferior, so 37 memory pools can be disabled to avoid excessive caching and force 38 atomic maintenance of chunks through the g_malloc/g_free. 39 Code currently affected by this macro: 40 - GList, GSList, GNode allocations 41 - GMemChunks become basically non-effective 42 - GSignal disables all caching (potentially very slow) 43 - GType doesn't honour the GTypeInfo n_preallocs field anymore 44 - the GBSearchArray flag G_BSEARCH_ALIGN_POWER2 becomes non-functional 45 G_DISABLE_ASSERT 46 The g_assert() and g_assert_not_reached() become non-functional 47 with this define. The motivation is to speed up end-user apps by 48 avoiding expensive checks. 49 This macro can affect third-party code. --enable-debug=no will only 50 disable the assertion macros for GLib itself, but third-party code 51 that passes -DG_DISABLE_ASSERT to the compiler upon its own build 52 will end up with the non-functional variants after including glib.h 53 as well. 54 NOTE: Code inside the assertion macros should not have side effects 55 that affect the operation of the program. 56 G_DISABLE_CHECKS 57 This macro is similar to G_DISABLE_ASSERT, it affects third-party 58 code as mentioned above and the NOTE about G_DISABLE_ASSERT applies 59 too. The macros that become non-functional here are 60 g_return_if_fail(), g_return_val_if_fail(), g_return_if_reached() and 61 g_return_val_if_reached(). 62 Additionally the glib_mem_profiler_table and g_mem_profile() from 63 gmem.h become non-functional if this macro is supplied. 64 This macro also switches off certain checks in the GSignal code. 65 G_ENABLE_DEBUG 66 Quite a bit of additional debugging code is compiled into GLib for this 67 macro, and since it is a globally visible define, third-party code may 68 be affected by it similar to G_DISABLE_ASSERT. 69 The additional code executed/compiled for this macro currently involve: 70 - extra validity checks for GDate 71 - memory profiling traps in gmem.c (consult debugging.txt for details) 72 - BREAKPOINT abortion for fatal log levels in gmessage.c instead of 73 plain abort() to allow debuggers trapping and overriding them 74 - added verbosity of gscanner.c to catch deprecated code paths 75 - added verbosity of gutils.c to catch deprecated code paths 76 - object ref/unref traps (consult debugging.txt) and object bookkeeping 77 in gobject.c 78 - extra validity checks in gsignal.c 79 80 81 2000/12/28 Tim Janik 82
