Re: evil hack in buffer.c, and need for internal docs onwidgetcode

Andy> Its in my inbug box :) I'm still trying to fix the crash Andy> that occurs when you select tabs. Stephen> Oh, that. Stephen> At line 2744 of src/glyphs-x.c: Stephen> XtSetArg (al [0], XtNtopWidget, child); Stephen> child can be NULL. I don't know how it gets that way. Stephen> :-) The patch below fixes the crash, but buggifies the tabs (that is, the current buffer and the tabs get unsynched each time the assert fails): Index: src/glyphs-x.c =================================================================== RCS file: /usr/CVSroot/XEmacs/xemacs/src/glyphs-x.c,v retrieving revision 1.49.2.76 diff -u -r1.49.2.76 glyphs-x.c --- glyphs-x.c 2000/08/06 09:27:15 1.49.2.76 +++ glyphs-x.c 2000/08/10 06:11:46 ＠＠ -2741,8 +2741,16 ＠＠ Widget child = XtNameToWidget (IMAGE_INSTANCE_X_WIDGET_ID (ii), cur->name); - XtSetArg (al [0], XtNtopWidget, child); - XtSetValues (IMAGE_INSTANCE_X_WIDGET_ID (ii), al, 1); + if (!child) + { + fprintf (stderr, "uh-oh, busted tabs! (buffer %s)\n", + cur->name ? cur->name : "NULL"); + } + else + { + XtSetArg (al [0], XtNtopWidget, child); + XtSetValues (IMAGE_INSTANCE_X_WIDGET_ID (ii), al, 1); + } break; } cur = cur->next; There are four buffers in the initial tabs: ben-mule.diff~, ben-mule.diff.orig, ben-mule.diff, and *Group* in that order. Clicking the tabs more or less randomly produces the following on stderr: bash-2.04$ uh-oh, busted tabs! (buffer ben-mule.diff~) uh-oh, busted tabs! (buffer ben-mule.diff.orig) uh-oh, busted tabs! (buffer ben-mule.diff.orig) uh-oh, busted tabs! (buffer ben-mule.diff.orig) uh-oh, busted tabs! (buffer ben-mule.diff~) uh-oh, busted tabs! (buffer ben-mule.diff~) uh-oh, busted tabs! (buffer ben-mule.diff~) uh-oh, busted tabs! (buffer ben-mule.diff~) uh-oh, busted tabs! (buffer ben-mule.diff.orig) uh-oh, busted tabs! (buffer ben-mule.diff.orig) uh-oh, busted tabs! (buffer ben-mule.diff~) uh-oh, busted tabs! (buffer ben-mule.diff~) uh-oh, busted tabs! (buffer ben-mule.diff~) uh-oh, busted tabs! (buffer ben-mule.diff~) uh-oh, busted tabs! (buffer ben-mule.diff~) uh-oh, busted tabs! (buffer ben-mule.diff~) uh-oh, busted tabs! (buffer ben-mule.diff~) uh-oh, busted tabs! (buffer ben-mule.diff.orig) There doesn't seem to be any way to get the error to occur for one of the other buffers, and they never end up in the leftmost positions; those are monopolized by the two buffers producing the error messages. I don't ever get a crash, so it's always a null Widget pointer when things are bogus. My hypothesis that the widget passed to XtNameToWidget might be bogus is presumably wrong; it's constant in the code. -- University of Tsukuba Tennodai 1-1-1 Tsukuba 305-8573 JAPAN Institute of Policy and Planning Sciences Tel/fax: +81 (298) 53-5091 _________________ _________________ _________________ _________________ What are those straight lines for? "XEmacs rules."