fixing -fvisibility-inlines-hidden problem (IsOk function didn't get exported)

[wxWidgets.git] / docs / tech / tn0020.txt

diff --git a/docs/tech/tn0020.txt b/docs/tech/tn0020.txt
index d8e875b4bedb9344c95b6efea1bfda31950d6928..bedf97cc302ea24106302d96c00e2e9e9c0a9186 100644 (file)
--- a/docs/tech/tn0020.txt
+++ b/docs/tech/tn0020.txt
@@ -60,7 +60,7 @@ The layout of wxABI_VERSION is as follows:
 
 where
 
- 20    60      2
+ 2     06     02
 Major Minor Release
 
 I.E. it corresponds to the wxWidgets release in {1}.
@@ -137,24 +137,94 @@ For ld/libtool we use sun-style version scripts.  Basically
 anything which fits the conditions of being ifed via wxABI_VERSION
 needs to go here also.
 
+See 'info ld scripts version' on a GNU system, it's online here:
+http://www.gnu.org/software/binutils/manual/ld-2.9.1/html_node/ld_25.html
+
+Or see chapter 5 of the 'Linker and Libraries Guide' for Solaris, available
+online here:
+http://docsun.cites.uiuc.edu/sun_docs/C/solaris_9/SUNWdev/LLM/p1.html
+
 The file has the layout as follows:
 
 @WX_VERSION_TAG@.X
 
 Where X is the current Release as mentioned earlier, i.e. 2.  This
 is following by an opening bracket "{", followed by "global:",
-followed by the added symbols, then followed by "}", and then
+followed by patterns matching added symbols, then followed by "}", and then
 the file is either followed by earlier Releases or ended by 
 a @WX_VERSION_TAG@ block without the period or Release.
 
-Added symbols have the form
-*CLASSNAME*METHODNAME*PARAM1*PARAM2*...
+The patterns used to specify added symbols are globbing patters and can
+contain wildcards such as '*'.
+
+For example for a new class member such as:
+    wxFont wxGenericListCtrl::GetItemFont( long item ) const;
+
+the mangled symbol might be:
+    _ZNK17wxGenericListCtrl11GetItemFontEl
+
+so a line like this could be added to version-script.in:
+    *wxGenericListCtrl*GetItemFont*;
+
+Allow for the fact that the name mangling is going to vary from compiler to
+complier.
+
+When adding a class you can match all the symbols it adds with a single
+pattern, so long as that pattern is not likely to also match other symbols.
+For example for wxLogBuffer a line like this:
+    *wxLogBuffer*;
+
+
+5.5. Checking the version information in libraries and programs
+---------------------------------------------------------------
+
+On Sun there is a tool for this, see pvs(1). On GNU you can use objdump, below
+are some examples.
+
+To see what versions of each library a program (or library) depends on:
+
+$ objdump -p widgets | sed -ne '/Version References/,/^$/p'
+Version References:
+  required from libgcc_s.so.1:
+    0x0b792650 0x00 10 GCC_3.0
+  required from libwx_based-2.6.so.0:
+    0x0cca2546 0x00 07 WXD_2.6
+  required from libstdc++.so.6:
+    0x056bafd3 0x00 09 CXXABI_1.3
+    0x08922974 0x00 06 GLIBCXX_3.4
+  required from libwx_gtk2d_core-2.6.so.0:
+    0x0a2545d2 0x00 08 WXD_2.6.2
+    0x0cca2546 0x00 05 WXD_2.6
+  required from libc.so.6:
+    0x09691a75 0x00 04 GLIBC_2.2.5
+
+To see what WXD_2.6.2 symbols a program uses:
+
+$ objdump -T widgets | grep 'WXD_2\.6\.2'
+0000000000000000 g    DO *ABS*  0000000000000000  WXD_2.6.2   WXD_2.6.2
+00000000004126d8      DF *UND*  0000000000000177  WXD_2.6.2   _ZN19wxTopLevelWindowGTK20RequestUserAttentionEi
+
+To see what WXD_2.6.2 symbols a library defines:
+
+$ objdump -T libwx_based-2.6.so | grep 'WXD_2\.6\.2' | grep -v 'UND\|ABS'
+0000000000259a10  w   DO .data  0000000000000018  WXD_2.6.2   _ZTI19wxMessageOutputBest
+00000000002599e0  w   DO .data  0000000000000028  WXD_2.6.2   _ZTV19wxMessageOutputBest
+000000000010a98e  w   DF .text  000000000000003e  WXD_2.6.2   _ZN19wxMessageOutputBestD0Ev
+0000000000114efb  w   DO .rodata        000000000000000e  WXD_2.6.2   _ZTS11wxLogBuffer
+0000000000255590  w   DO .data  0000000000000018  WXD_2.6.2   _ZTI11wxLogBuffer
+000000000011b550  w   DO .rodata        0000000000000016  WXD_2.6.2   _ZTS19wxMessageOutputBest
+00000000000bfcc8 g    DF .text  00000000000000dd  WXD_2.6.2   _ZN11wxLogBuffer5DoLogEmPKcl
+000000000010a3a6 g    DF .text  0000000000000153  WXD_2.6.2   _ZN19wxMessageOutputBest6PrintfEPKcz
+00000000000c0b22  w   DF .text  000000000000004b  WXD_2.6.2   _ZN11wxLogBufferD0Ev
+00000000000bfc3e g    DF .text  0000000000000089  WXD_2.6.2   _ZN11wxLogBuffer5FlushEv
+00000000000c0ad6  w   DF .text  000000000000004b  WXD_2.6.2   _ZN11wxLogBufferD1Ev
+00000000000b1130  w   DF .text  0000000000000036  WXD_2.6.2   _ZN11wxLogBufferC1Ev
+00000000000c095c  w   DF .text  0000000000000029  WXD_2.6.2   _ZN19wxMessageOutputBestC1Ev
+00000000000c08e8  w   DF .text  000000000000003e  WXD_2.6.2   _ZN19wxMessageOutputBestD1Ev
+00000000002554c0  w   DO .data  0000000000000038  WXD_2.6.2   _ZTV11wxLogBuffer
+00000000000bfda6 g    DF .text  0000000000000036  WXD_2.6.2   _ZN11wxLogBuffer11DoLogStringEPKcl
+00000000000abe10 g    DF .text  0000000000000088  WXD_2.6.2   _ZN14wxZipFSHandler7CleanupEv
 
-Where CLASSNAME is the name of the class or blank (along with
-omitted *) in the case of a global function.  METHODNAME is the name
-of the class method or global function.  This is followed by another
-star "*" and then the type of each subsequent parameter for the function,
-such as *wxString etc..
 
 6. Testing binary compatability between releases
 ------------------------------------------------
@@ -169,6 +239,10 @@ You can also break into your debugger or whatever program you want
 to use and check the memory layout of the class.  If it is the same
 then it is binary compatable.
 
+Also remember to look at http://www.wxwidgets.org/bincompat.html page which
+summarizes the results of testing of all the samples built against old
+libraries headers with the new library binaries under Unix.
+
 
 === EOF ===