LB_INITSTORAGE message

Allocates memory for storing list box items. This message can be used before an application adds a large number of items to a list box.

Parameters

wParam

The number of items for which to reserve space.

Windows 95/Windows 98/Windows Millennium Edition (Windows Me) : The wParam parameter is limited to 16-bit values. This means list boxes cannot contain more than 32,767 items. Although the number of items is restricted, the total size in bytes of the items in a list box is limited only by available memory.

lParam

The amount of additional memory, in bytes, to allocate for item strings.

Return value

If the message is successful, the return value is the total number of items that the list box can store before a memory reallocation is needed.

If the message fails, the return value is LB_ERRSPACE.

Microsoft Windows NT 4.0 : This message does not allocate the specified amount of memory; however, it always returns the value specified in the wParam parameter.

Remarks

The LB_INITSTORAGE message helps speed up the initialization of list boxes that have a large number of items (more than 100). It reserves the specified amount of memory so that subsequent LB_ADDSTRING, LB_INSERTSTRING, LB_DIR, and LB_ADDFILE messages are more efficient. You can use estimates for the wParam and lParam parameters. If you overestimate, the extra memory remains allocated; if you underestimate, the list box will allocate additional memory as necessary.

The memory required to store a string includes the null terminator. Therefore, if you plan to add 100 strings, each with a length of 10 characters, you would pass a wParam of 100 and an lParam of 100 × (10 + 1) × sizeof(TCHAR).

Requirements

See also

Reference

LB_ADDFILE

LB_ADDSTRING

LB_DIR

LB_INSERTSTRING