We usually zero-initialize vectors like string_vector names = empty_vector;
Allocating and zeroing separately is frequently useful however. Document the pattern string_vector names; names = (string_vector)empty_vector; where "(string_vector)empty_vector" is a compound literal. Link: 20230221183810.vjilfbmj3woqivlj@redhat.com">http://mid.mail-archive.com/20230221183810.vjilfbmj3woqivlj@redhat.com Suggested-by: Eric Blake <ebl...@redhat.com> Signed-off-by: Laszlo Ersek <ler...@redhat.com> --- Notes: I'll pick this patch to libnbd as well, once merged in nbdkit. context:-U10 common/utils/vector.h | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/common/utils/vector.h b/common/utils/vector.h index ac28c0b5363a..7337d26893eb 100644 --- a/common/utils/vector.h +++ b/common/utils/vector.h @@ -55,28 +55,34 @@ /* Use of this macro defines a new type called ‘name’ containing an * extensible vector of ‘type’ elements. For example: * * DEFINE_VECTOR_TYPE (string_vector, char *); * * defines a new type called ‘string_vector’ as a vector of ‘char *’. * You can create variables of this type: * * string_vector names = empty_vector; * + * or + * + * string_vector names; + * names = (string_vector)empty_vector; + * * where ‘names.ptr[]’ will be an array of strings and ‘names.len’ * will be the number of strings. There are no get/set accessors. To * iterate over the strings you can use the ‘.ptr’ field directly: * * for (size_t i = 0; i < names.len; ++i) * printf ("%s\n", names.ptr[i]); * - * Initializing with ‘empty_vector’ sets ‘.ptr = NULL’ and ‘.len = 0’. + * Initializing with ‘empty_vector’, or assigning the compound literal + * ‘(string_vector)empty_vector’, sets ‘.ptr = NULL’ and ‘.len = 0’. * * DEFINE_VECTOR_TYPE also defines utility functions. For the full * list see the definition below, but useful functions include: * * ‘name’_append (eg. ‘string_vector_append’) * - Append a new element at the end. This operation is cheap. * * ‘name’_insert (eg. ‘string_vector_insert’) * - Insert a new element at the beginning, middle or end. This * operation is more expensive because existing elements may need _______________________________________________ Libguestfs mailing list Libguestfs@redhat.com https://listman.redhat.com/mailman/listinfo/libguestfs
