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From: "msebor at redhat dot com" <sourceware-bugzilla@sourceware.org> To: gdb-prs@sourceware.org Subject: [Bug c++/18888] New: unable to evaluate NULL Date: Fri, 28 Aug 2015 21:49:00 -0000 [thread overview] Message-ID: <bug-18888-4717@http.sourceware.org/bugzilla/> (raw) https://sourceware.org/bugzilla/show_bug.cgi?id=18888 Bug ID: 18888 Summary: unable to evaluate NULL Product: gdb Version: 7.8 Status: NEW Severity: normal Priority: P2 Component: c++ Assignee: unassigned at sourceware dot org Reporter: msebor at redhat dot com Target Milestone: --- GNU gdb (GDB) Fedora 7.8.2-38.fc21 doesn't seem to know about GCC's __null extension used to implement the NULL macro. When the NULL macro is used in the definition of a function like macro as happens to be the case with some of the GCC tree checking macros such as DECL_ASSEMBLER_NAME_SET_P, GDB issues the cryptic error 'No symbol "__null" in current context.' when an attempt is to evaluate an invocation of the macro. This makes GCC debugging harder than it would be otherwise. (gdb) p DECL_ASSEMBLER_NAME_SET_P(expr) No symbol "__null" in current context. Test case: $ cat t.c && g++ -g3 t.c && gdb -batch -ex 'b main' -ex 'r' -ex 'macro expand FOO(p, 1, 2)' -ex 'p FOO(p, 1, 2)' a.out #include <stdlib.h> #define FOO(a, b, c) a == NULL ? b : c int main () { void *p = NULL; int n; n = FOO (p, 1, 2); return n; } Breakpoint 1 at 0x4005ba: file t.c, line 7. Breakpoint 1, main () at t.c:7 7 void *p = NULL; expands to: p == __null ? 1 : 2 No symbol "__null" in current context. -- You are receiving this mail because: You are on the CC list for the bug.
next reply other threads:[~2015-08-28 21:49 UTC|newest] Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top 2015-08-28 21:49 msebor at redhat dot com [this message] 2022-04-02 16:48 ` [Bug c++/18888] " tromey at sourceware dot org
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