I have a followup gdb 101 question: I thought I would improve the debug capability by adding the flags "--enable-checking='yes,glyphs' --enable-check-lisp-object-type" to ./configure as per etc/DEBUG. I did not have those 2 flags earlier. But after rebuilding using the suggested options, the conditional breakpoints do not work. I also noticed that earlier "p error_symbol" gave something like, $1 = 41328 Now it gives something like, $1 = { i = 41328 } Also, when earlier I saw: Breakpoint 3, Fsignal (error_symbol=19056, data=16197139) at eval.c:1471 , now I see instead: Breakpoint 3, Fsignal (error_symbol=..., data=...) at eval.c:1471 (those numbers for error_symbol and data are literally replaced with "...") ===== (emacs:22439): GLib-GIO-CRITICAL **: g_settings_schema_source_lookup: assertion 'source != NULL' failed Breakpoint 3, Fsignal (error_symbol=..., data=...) at eval.c:1471 1471 = (NILP (error_symbol) ? Fcar (data) : error_symbol); (gdb) p error_symbol $1 = { i = 41328 } (gdb) xsymbol $2 = (struct Lisp_Symbol *) 0xdc3ee0 "scan-error" (gdb) condition 3 error_symbol!=41328 (gdb) c Continuing. Error in testing breakpoint condition: Structure has no component named operator!=. Error in testing breakpoint condition: Structure has no component named operator!=. Breakpoint 3, Fsignal (error_symbol=..., data=...) at eval.c:1471 1471 = (NILP (error_symbol) ? Fcar (data) : error_symbol); Here's my new ./configure command: ./configure options: --with-modules --prefix=/home/kmodi/usr_local/apps/6/emacs/emacs-25 --enable-checking=yes,glyphs --enable-check-lisp-object-type 'CPPFLAGS=-fgnu89-inline -I/home/kmodi/usr_local/6/include -I/usr/include/freetype2 -I/usr/include' 'CFLAGS=-ggdb3 -O0' 'CXXFLAGS=-ggdb3 -O0' 'LDFLAGS=-L/home/kmodi/usr_local/6/lib -L/home/kmodi/usr_local/6/lib64 -ggdb3' PKG_CONFIG_PATH=/home/kmodi/usr_local/6/lib/pkgconfig:/home/kmodi/usr_local/6/lib64/pkgconfig:/cad/adi/apps/gnu/linux/x86_64/6/lib/pkgconfig:/cad/adi/apps/gnu/linux/x86_64/6/lib64/pkgconfig:/usr/lib/pkgconfig:/usr/lib64/pkgconfig:/usr/share/pkgconfig:/lib/pkgconfig:/lib64/pkgconfig For now, I will rebuild emacs without "--enable-checking='yes,glyphs' --enable-check-lisp-object-type". But it would be good to know why those flags affected gdb (when etc/DEBUG says that those should not), and also why didn't conditional breakpoints work in this case. (I hope to get the old conditional-breakpoint-working-self back once I finish rebuilding without those flags.) -- -- Kaushal Modi