Retrieve an environment variable

ContextKeyword lcxk_base
string ls_Path
string ls_values[]

this.GetContextService("Keyword", lcxk_base)
lcxk_base.GetContextKeywords("path", ls_values)
IF Upperbound(ls_values) > 0 THEN
   ls_Path = ls_values[1]
ELSE
   ls_Path = "*UNDEFINED*"
END IF

ALLUSERSPROFILE      location of the All Users Profile.
APPDATA              location where applications store data by default.
CD                   current directory string.
CLIENTNAME           client's NETBIOS name when connected to terminal server session.
CMDCMDLINE           command line used to start the current cmd.exe.
CMDEXTVERSION        version number of the current Command Processor Extensions.
CommonProgramFiles   path to the Common Files folder.
COMPUTERNAME         name of the computer.
COMSPEC              path to the command shell executable.
DATE                 current date.
ERRORLEVEL           error code of the most recently used command.
HOMEDRIVE            drive letter is connected to the user's home directory.
HOMEPATH             full path of the user's home directory.
HOMESHARE            network path to the user's shared home directory.
LOGONSEVER           name of the domain controller that validated the current logon session.
NUMBER_OF_PROCESSORS   number of processors installed on the computer.
OS                   name of the operating system.
                     (Windows XP and Windows 2000 list the operating system as Windows_NT.)
Path                 search path for executable files.
PATHEXT              file extensions that the operating system considers to be executable.
PROCESSOR_ARCHITECTURE   processor's chip architecture.
PROCESSOR_IDENTFIER  description of the processor.
PROCESSOR_LEVEL      model number of the computer's processor.
PROCESSOR_REVISION   revision number of the processor.
ProgramFiles         path to the Program Files folder.
PROMPT               command-prompt settings for the current interpreter.
RANDOM               random decimal number between 0 and 32767.
SESSIONNAME          connection and session names when connected to terminal server session.
SYSTEMDRIVE          drive containing the Windows root directory.
SYSTEMROOT           location of the Windows root directory.
TEMP and TMP         default temporary directories for applications that are available to
                     users who are currently logged on.
TIME                 current time.
USERDOMAIN           name of the domain that contains the user's account.
USERNAME             name of the user currently logged on.
USERPROFILE          location of the profile for the current user.
WINDIR               location of the OS directory.

In this example, we populate a listbox with the printers name

/* Get Printer List */
string printers[]
int rtn, i, nbPrinters
rtn = RegistryKeys &
   ("HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Print\Printers", &
      printers)
nbPrinters = UpperBound(printers)
FOR i = 1 TO nbPrinters
    lb_1.addItem(printers[i])
NEXT

You can list available ODBC datasources from within PowerBuilder. You need to declare the following external functions :

FUNCTION integer SQLAllocEnv(ref long henv) LIBRARY "odbc32.dll"
FUNCTION integer SQLFreeEnv(long henv) LIBRARY "odbc32.dll"
FUNCTION integer SQLDataSources &
(long henv, integer idirection, ref string szdsn, int idsnmax, &
ref integer idsn, ref string szdesc, integer idescmax, ref integer idesc) &
library "odbc32.dll"

long ll_henv
string ls_dsn, ls_desc
integer li_direction, li_dsnmax, li_dsnlen, li_descmax, li_desclen, li_rc
integer li_length = 255

ls_dsn = Space(li_length)
li_dsnmax = li_length
ls_desc = Space(li_length)
li_descmax = li_length

IF SQLAllocEnv(ll_henv) = -1 THEN
    MessageBox("SQLAllocEnv", "FAILURE")
ELSE
    li_direction = 1
    DO WHILE SQLDataSources &
        (ll_henv, li_direction, ls_dsn, li_dsnmax, li_dsnlen, &
         ls_desc, li_descmax, li_desclen) = 0
         ddlb_1.AddItem(ls_dsn + "  [" + ls_desc + "]")
    LOOP
    SQLFreeEnv(ll_henv)
END IF

These useful informations can be retrieved via direct calls to the ODBC API. This way we don't need DBMS-specific SELECT statement.
External Function Declaration :

FUNCTION integer SQLGetInfo  &
  (long hconn, integer infotype, ref string infotypeptr, &
   integer bufferlength, ref integer bufferlengthptr) &
  LIBRARY "odbc32.dll"

string ls_dbms, ls_database, ls_user
integer li_length
CONSTANT integer SQL_DBMS_NAME = 17
CONSTANT integer SQL_DATABASE_NAME = 16
CONSTANT integer SQL_USER_NAME = 47
long   ll_dbhandle

ls_dbms = space(256)
ls_database = space(256)
ls_user = space(256)
ll_dbhandle = SQLCA.DbHandle()
SQLGetInfo(ll_dbhandle, SQL_DBMS_NAME, ls_dbms, 255, li_length)
SQLGetInfo(ll_dbhandle, SQL_DATABASE_NAME, ls_database, 255, li_length)
SQLGetInfo(ll_dbhandle, SQL_USER_NAME, ls_user, 255, li_length)

MessageBox("Current DBMS" , trim(ls_dbms))
MessageBox("Current DATABASE" , trim(ls_database))
MessageBox("Current USER" , trim(ls_user))

Here's a script to sort datawindow rows when the column header is clicked as in windows explorer.
Requirements : Column header should be same as column name and ended with '_t'. For Example, Column Name : 'emp_id'
Column Header : 'emp_id_t'
Condition : Only one column can sort at a time.

String ls_old_sort, ls_column
Char lc_sort
/* Check whether the user clicks on the column header */
IF Right(dwo.Name,2) = '_t' THEN
    ls_column = LEFT(dwo.Name, LEN(String(dwo.Name)) - 2)
    /* Get old sort, if any. */
    ls_old_sort = dw_1.Describe("Datawindow.Table.sort")
    /* Check whether previously sorted column and currently clicked column are same or not. If     both are same then check for the sort order of previously sorted column (A - Asc, D - Des) and     change it. If both are not same then simply sort it by Ascending order. */
    IF ls_column = LEFT(ls_old_sort, LEN(ls_old_sort) - 2) THEN
         lc_sort = RIGHT(ls_old_sort, 1)
        IF lc_sort = 'A' THEN
             lc_sort = 'D'
        ELSE
             lc_sort = 'A'
        END IF
        dw_1.SetSort(ls_column+" "+lc_sort)
    ELSE
        dw_1.SetSort(ls_column+" A")
    END IF
    dw_1.Sort()
END IF

Here's function to convert Hexadecimal number to Decimal number

/**********************************************/
/*  public long uf_Hex2Dec ( string as_Hex )  */
/**********************************************/

CONSTANT STRING ls_HexSet = "0123456789ABCDEF"

STRING  ls_Hex, ls_Bit
LONG    ll_Div, ll_RetVal = 0
INTEGER li_C, li_Len, li_Pos
BOOLEAN lb_Error = FALSE

ls_Hex = Upper( as_Hex )

IF NOT IsNull( ls_Hex ) AND ls_Hex <> "" THEN
   
    li_Len = Len( ls_Hex )
   
    FOR li_C = 1 TO li_Len
        ls_Bit = Mid( ls_Hex, li_C, 1 )
        li_Pos = Pos( ls_HexSet, ls_Bit )
       
        IF li_Pos = 0 THEN
            lb_Error = TRUE
        ELSE
            ll_RetVal += ( ( li_Pos - 1 ) * ( 16 ^ ( li_Len - li_C ) ) )
        END IF
    NEXT
    IF lb_Error THEN ll_RetVal = 0
END IF

RETURN ll_RetVal

Here's a function to calculate Julian Day number for the specified day, month, year. If the year is B.C. it must be negative.

/*  public long uf_JulianDate ( integer ai_Day, integer ai_Month, integer ai_Year )   */
DOUBLE  lr_ycorr
LONG    ll_Day, ll_Month, ll_Year, ll_ca, ll_cb, ll_RetVal = 0

ll_Day = Long( ai_Day );  ll_Month = Long( ai_Month );  ll_Year = Long( ai_Year );

IF ll_Day > 0 OR ll_Month > 0 OR ll_Year > 0 THEN
    IF ll_Year > 0 THEN
        lr_ycorr = 0.0
    ELSE
        lr_ycorr = 0.75
    END IF
    
    if ll_Month <= 2 THEN
        ll_Year  = Long( ll_Year  -  1 )
        ll_Month = Long( ll_Month + 12 )
    END IF
   
    ll_cb = 0
   
    IF ( ( Double( ll_Year ) * Double( 10000.0 ) + Double( ll_Month ) * Double( 100.0 ) + &
         Double( ll_Day ) ) >= Double( 15821015.0 ) ) THEN
      ll_ca = Long( ll_Year / 100 )
        ll_cb = Long( 2 - ll_ca ) + Long( ll_ca / 4 )
    END IF
   
    ll_RetVal = Long( Double( 365.25  ) * Double( ll_Year ) - lr_ycorr ) +  &
                    Long( Double( 30.6001 ) * Double( ll_Month + 1 ) ) +  &
                    Long( Double( ll_Day  ) + Double( 1720994.5 ) + Double( ll_cb ) )
END IF

RETURN ll_RetVal