On Mon, Oct 28, 2024 at 12:48 PM Jan Beulich <[email protected]> wrote: > > On 28.10.2024 13:03, Andrew Cooper wrote: > > On 28/10/2024 11:48 am, Roger Pau Monne wrote: > >> Clang 19 complains with the following error when building libxl: > >> > >> libxl_utils.c:48:15: error: variable length array folded to constant array > >> as an extension [-Werror,-Wgnu-folding-constant] > >> 48 | char path[strlen("/local/domain") + 12]; > >> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~ > >> > >> Replace the usage of strlen() with ARRAY_SIZE(), which allows the literal > >> string length to be known at build time. Note ARRAY_SIZE() accounts for > >> the > >> NUL terminator while strlen() didn't, hence subtract 1 from the total size > >> calculation. > >> > >> Signed-off-by: Roger Pau Monné <[email protected]> > >> --- > >> tools/libs/light/libxl_utils.c | 4 ++-- > >> 1 file changed, 2 insertions(+), 2 deletions(-) > >> > >> diff --git a/tools/libs/light/libxl_utils.c > >> b/tools/libs/light/libxl_utils.c > >> index 10398a6c8611..b3f5e751cc3f 100644 > >> --- a/tools/libs/light/libxl_utils.c > >> +++ b/tools/libs/light/libxl_utils.c > >> @@ -45,7 +45,7 @@ unsigned long libxl_get_required_shadow_memory(unsigned > >> long maxmem_kb, unsigned > >> char *libxl_domid_to_name(libxl_ctx *ctx, uint32_t domid) > >> { > >> unsigned int len; > >> - char path[strlen("/local/domain") + 12]; > >> + char path[ARRAY_SIZE("/local/domain") + 11]; > >> char *s; > >> > >> snprintf(path, sizeof(path), "/local/domain/%d/name", domid); > >> @@ -141,7 +141,7 @@ int libxl_cpupool_qualifier_to_cpupoolid(libxl_ctx > >> *ctx, const char *p, > >> char *libxl_cpupoolid_to_name(libxl_ctx *ctx, uint32_t poolid) > >> { > >> unsigned int len; > >> - char path[strlen("/local/pool") + 12]; > >> + char path[ARRAY_SIZE("/local/pool") + 11]; > >> char *s; > >> > >> snprintf(path, sizeof(path), "/local/pool/%d/name", poolid); > > > > Acked-by: Andrew Cooper <[email protected]> > > > > Although I have a minor preference for sizeof() as suggested by Frediano. > > > > Can fix on commit, if you're happy? > > Please can we stick to ARRAY_SIZE() when it comes to strings? It's the > same as sizeof() when the base type is char, but the difference becomes > relevant if the base type was e.g. wchar_t. > > Jan >
But "literal" is not a wide string, and the type is "char" which is not wide too. BTW, both me and Andrew are not strong about. Frediano
