[libvirt] one more warning

One more warning question: Compiling with all storage backends disabled, I get this: storage_backend.c:91: warning: comparison of unsigned expression < 0 is always false That's because of this code: static virStorageBackendPtr backends[] = { #if WITH_STORAGE_DIR &virStorageBackendDirectory, #endif #if WITH_STORAGE_FS &virStorageBackendFileSystem, &virStorageBackendNetFileSystem, #endif #if WITH_STORAGE_LVM &virStorageBackendLogical, #endif #if WITH_STORAGE_ISCSI &virStorageBackendISCSI, #endif #if WITH_STORAGE_DISK &virStorageBackendDisk, #endif }; virStorageBackendPtr virStorageBackendForType(int type) { unsigned int i; for (i = 0 ; i < ARRAY_CARDINALITY(backends); i++) if (backends[i]->type == type) return backends[i]; virStorageReportError(NULL, VIR_ERR_INTERNAL_ERROR, _("missing backend for pool type %d"), type); return NULL; } The above loses because ARRAY_CARDINALITY(backends) is 0. One solution is to always have at least one backend, e.g., the first one, in which case, this patch works fine: [but if you like this (i don't), it'd make sense also to remove the configure-time option ] diff --git a/src/storage_backend.c b/src/storage_backend.c index e33f98c..264cc53 100644 --- a/src/storage_backend.c +++ b/src/storage_backend.c @@ -56,9 +56,7 @@ #if WITH_STORAGE_DISK #include "storage_backend_disk.h" #endif -#if WITH_STORAGE_DIR #include "storage_backend_fs.h" -#endif VIR_ENUM_IMPL(virStorageBackendPartTable, VIR_STORAGE_POOL_DISK_LAST, @@ -66,9 +64,7 @@ VIR_ENUM_IMPL(virStorageBackendPartTable, "mac", "bsd", "pc98", "sun", "lvm2"); static virStorageBackendPtr backends[] = { -#if WITH_STORAGE_DIR &virStorageBackendDirectory, -#endif #if WITH_STORAGE_FS &virStorageBackendFileSystem, &virStorageBackendNetFileSystem, Another way is to add a NULL pointer at the end and change the loop not to use the array size at all: for (i = 0; backends[i]; i++) if (backends[i]->type == type) return backends[i]; I chose the latter: diff --git a/src/storage_backend.c b/src/storage_backend.c index e33f98c..1f4ed10 100644 --- a/src/storage_backend.c +++ b/src/storage_backend.c @@ -82,13 +82,14 @@ static virStorageBackendPtr backends[] = { #if WITH_STORAGE_DISK &virStorageBackendDisk, #endif + NULL }; virStorageBackendPtr virStorageBackendForType(int type) { unsigned int i; - for (i = 0 ; i < ARRAY_CARDINALITY(backends); i++) + for (i = 0; backends[i]; i++) if (backends[i]->type == type) return backends[i];