Using Singly Linked Lists

The following example uses the InitializeSListHead function to initialize a singly linked list and the InterlockedPushEntrySList function to insert 10 items. The example uses the InterlockedPopEntrySList function to remove 10 items and the InterlockedFlushSList function to verify that the list is empty.

#include <windows.h>
#include <malloc.h>
#include <stdio.h>

// Structure to be used for a list item; the first member is the 
// SLIST_ENTRY structure, and additional members are used for data.
// Here, the data is simply a signature for testing purposes. 


typedef struct _PROGRAM_ITEM {
    SLIST_ENTRY ItemEntry;
    ULONG Signature; 
} PROGRAM_ITEM, *PPROGRAM_ITEM;

int main( )
{
    ULONG Count;
    PSLIST_ENTRY pFirstEntry, pListEntry;
    PSLIST_HEADER pListHead;
    PPROGRAM_ITEM pProgramItem;

    // Initialize the list header to a MEMORY_ALLOCATION_ALIGNMENT boundary.
    pListHead = (PSLIST_HEADER)_aligned_malloc(sizeof(SLIST_HEADER),
       MEMORY_ALLOCATION_ALIGNMENT);
    if( NULL == pListHead )
    {
        printf("Memory allocation failed.\n");
        return -1;
    }
    InitializeSListHead(pListHead);

    // Insert 10 items into the list.
    for( Count = 1; Count <= 10; Count += 1 )
    {
        pProgramItem = (PPROGRAM_ITEM)_aligned_malloc(sizeof(PROGRAM_ITEM),
            MEMORY_ALLOCATION_ALIGNMENT);
        if( NULL == pProgramItem )
        {
            printf("Memory allocation failed.\n");
            return -1;
        }
        pProgramItem->Signature = Count;
        pFirstEntry = InterlockedPushEntrySList(pListHead, 
                       &(pProgramItem->ItemEntry)); 
    }

    // Remove 10 items from the list and display the signature.
    for( Count = 10; Count >= 1; Count -= 1 )
    {
        pListEntry = InterlockedPopEntrySList(pListHead);

        if( NULL == pListEntry )
        {
            printf("List is empty.\n");
            return -1;
        }
  
        pProgramItem = (PPROGRAM_ITEM)pListEntry;
        printf("Signature is %d\n", pProgramItem->Signature);

    // This example assumes that the SLIST_ENTRY structure is the 
    // first member of the structure. If your structure does not 
    // follow this convention, you must compute the starting address 
    // of the structure before calling the free function.

        _aligned_free(pListEntry);
    }

    // Flush the list and verify that the items are gone.
    pListEntry = InterlockedFlushSList(pListHead);
    pFirstEntry = InterlockedPopEntrySList(pListHead);
    if (pFirstEntry != NULL)
    {
        printf("Error: List is not empty.\n");
        return -1;
    }

    _aligned_free(pListHead);

    return 1;
}