Re: [libvirt] [PATCH] build: detect potentential uninitialized variables

Even with -Wuninitialized (which is part of autobuild.sh --enable-compile-warnings=error), gcc does NOT catch this use of an uninitialized variable: {  if (cond)    goto error;  int a = 1; error:  printf("%d", a); } which prints 0 (if the stack was previously wiped) if cond was true.  Clang will catch it, but we dont' use clang as often.  Using gcc -Wjump-misses-init gives false positives: {  if (cond)    goto error;  int a = 1;  return a; error:  return 0; } Here, a was never used in the scope of the error block, so declaring it after goto is technically fine (and clang agrees); however, given that our HACKING already documents a preference to C89 decl-before-statement, the false positive warning is enough of a prod to comply with HACKING. [Personally, I'd _really_ rather use C99 decl-after-statement to minimize scope, but until gcc can efficiently and reliably catch scoping and uninitialized usage bugs, I'll settle with the compromise of enforcing a coding standard that rejects false positives.]

diff --git a/src/qemu/qemu_hotplug.c b/src/qemu/qemu_hotplug.c index 9082515..b03f774 100644 --- a/src/qemu/qemu_hotplug.c +++ b/src/qemu/qemu_hotplug.c @@ -51,8 +51,8 @@ int qemuDomainChangeEjectableMedia(struct qemud_driver *driver,     int i;     int ret;     char *driveAlias = NULL; +    qemuDomainObjPrivatePtr priv; -    origdisk = NULL;     for (i = 0 ; i < vm->def->ndisks ; i++) {         if (vm->def->disks[i]->bus == disk->bus &&             STREQ(vm->def->disks[i]->dst, disk->dst)) {