How do I sort a container control?

/*
 * Note that PSESSION is my own instance data structure.
 * I use it here to retrieve the type of field comparison I should do.
 */

 static SHORT APIENTRY Compare (PMINIRECORDCORE pmrc1,
                                PMINIRECORDCORE pmrc2,
                                PVOID pvStorage)
 {
    PSESSION pSession = (PSESSION) pvStorage ;
    PFIELDINFO pFieldInfo = pSession->pFieldInfoSort ;
    PPVOID pField1 = (PPVOID) ((PBYTE) pmrc1 +
       pFieldInfo->offStruct) ;
    PPVOID pField2 = (PPVOID) ((PBYTE) pmrc2 +
       pFieldInfo->offStruct) ;
    SHORT sResult = 0 ;

    if (pFieldInfo->flData & CFA_STRING) {
       sResult = strcmp ((PCHAR) *pField1, (PCHAR) *pField2) ;
    }
    else if (pFieldInfo->flData & CFA_ULONG) {
       if ((ULONG) *pField1 < (ULONG) *pField2)
          sResult = -1 ;
       else if ((ULONG) *pField1 > (ULONG) *pField2)
          sResult = 1 ;
       else
          sResult = 0 ;
    }
    else if (pFieldInfo->flData & CFA_DATE) {
       sResult = CompareDate ((PCDATE) (PVOID) pField1,
                              (PCDATE) (PVOID) pField2) ;
    }
    else if (pFieldInfo->flData & CFA_TIME) {
       sResult = CompareTime ((PCTIME) (PVOID) pField1,
                              (PCTIME) (PVOID) pField2) ;
    }

    // Any other data type gets treated as equal;
    // no sorting can be done. Now handle reverse sequence.
    if (pSession->fSortReverse && sResult)
       sResult = -sResult ;
    return sResult ;
 }

Here is how I invoke the sort:

 // Send container a sort message.
 ulRC = LONGFROMMR (WinSendMsg (
                    pSession->hwndContainer,
                    CM_SORTRECORD,
                    MPFROMP (Compare), MPFROMP (pSession))) ;
 if (!ulRC) {
    // Report error.
 }

Credit: Wayne Kovsky