Struct initialisation

[Allan Bruce]

I have made a struct which has several fields and I initialise like this:

MyStruct foo = {a, b, c, d, e};

I just added another field to the struct at the end, and I thought I would
have to add this new field to all of the initialisers but I dont, is this
defined behaviour?
Thanks
Allan



Here is my code:


/* define struct */
typedef struct
{
HWND xiParentWnd;
const char *xiCaption;
const char *xiTitle;
DWORD xiFlags;
DWORD xiNotifyMsg;
bool AutoDelete;
} AsyncMessageBoxInfo;


/* an example initialising the strcut */
AsyncMessageBoxInfo lAMBI = {NULL, "User is no longer logged in",
mRemoteUser, MB_OK | WS_EX_TOPMOST, NULL};

 

[Vijay Kumar R Zanvar]

I have made a struct which has several fields and I initialise like this:

MyStruct foo = {a, b, c, d, e};

I just added another field to the struct at the end, and I thought I would
have to add this new field to all of the initialisers but I dont, is this
defined behaviour?
Thanks
Allan



Here is my code:


/* define struct */
typedef struct
{
HWND xiParentWnd;
const char *xiCaption;
const char *xiTitle;
DWORD xiFlags;
DWORD xiNotifyMsg;
bool AutoDelete;
} AsyncMessageBoxInfo;


/* an example initialising the strcut */
AsyncMessageBoxInfo lAMBI = {NULL, "User is no longer logged in",
mRemoteUser, MB_OK | WS_EX_TOPMOST, NULL};

Perfectly defined behaviour. AutoDelete would be set to zero.
I think `bool' is of an integral type.

Vijay

 

[Leor Zolman]

I have made a struct which has several fields and I initialise like this:

MyStruct foo = {a, b, c, d, e};

I just added another field to the struct at the end, and I thought I would
have to add this new field to all of the initialisers but I dont, is this
defined behaviour?
Thanks
Allan

Yes. 6.7.8/19 of the Standard says:

"The initialization shall occur in initializer list order, each initializer
provided for a particular subobject overriding any previously listed
initializer for the same subobject; all subobjects that are not initialized
explicitly shall be initialized implicitly the same as objects that have
static storage duration."

This applies to both arrays and structs; it seems to get discussed more
often in the context of array initialization, however (in fact, I
misinterpreted it just the other day...)
-leor