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**OPEN(**// entity// [,// access mode / owner //] **)**

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| **OPEN** | Opens a FILE, VIEW, APPLICATION, WINDOW, or REPORT structure for processing. |
| //entity// | The label of a FILE, VIEW, APPLICATION, WINDOW, or REPORT structure. |
| //access mode// | A numeric constant, variable, or expression which determines the level of access granted to both the user opening the FILE //entity//, and other users in a multi-user system. If omitted, the default value is 22h (Read/Write + Deny Write). Valid only when the //entity// parameter names a FILE structure. |
| //owner// | The label of the APPLICATION or WINDOW structure which "owns" the window //entity// being opened//. //Normally, this parameter would be an &WINDOW reference variable. Valid only when the //entity// parameter names an APPLICATION or WINDOW structure. |

The **OPEN** statement opens a FILE, VIEW, APPLICATION, WINDOW, or REPORT structure for processing.

**FILE Usage**

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The OPEN statement opens a FILE structure for processing and sets the //access mode//. Support for various //access modes// are file driver dependent. All files must be explicitly opened before the records may be accessed.

The //access mode// is a bitmap which tells the operating system what access to grant the user opening the file and what access to deny to others using the file.

The actual values for each access level are:

** **__**Dec **__** **__**Hex**__** **__**Access**__

**User Access:**

** 0    0h   Read Only**

** 1    1h   Write Only**

** 2    2h   Read/Write**

**Other's Access:**

**  0   0h   Any Access (FCB compatibility mode)**

**  16  10h  Deny All**

**  32  20h  Deny Write**

**  48  30h  Deny Read**

**  64  40h  Deny None**

**VIEW Usage**

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The OPEN statement opens a VIEW structure for processing. A VIEW must be explicitly opened before it may be accessed. The files used in the VIEW must already be open.

Before the OPEN(//view//) statement, you may issue a SET statement to the VIEW structure's primary file to setup sequential processing for the VIEW. You cannot issue a SET statement to the primary file while the VIEW is OPEN--you must CLOSE(//view//), then issue the SET,and then OPEN(//view//) again. SET(//view//) may be issued while the VIEW is open to setup sequential processing using the ORDER attribute.

**Window Usage**

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OPEN activates an APPLICATION or WINDOW for processing. However, nothing is displayed until a DISPLAY statement or the ACCEPT loop is encountered. This allows an opportunity to execute pre-display code to customize the display.

A //window// with an //owner// always appears on top of its //owner//, and is automatically hidden if the //owner// is minimized or hidden. If the //owner// is closed, all owned windows are also automatically closed. MDI windows are implicitly owned by the frame window. Non-MDI windows do not have an //owner// by default.

**REPORT Usage**

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OPEN activates a REPORT structure. You must explicitly OPEN a REPORT before any of the structures may be printed.

**Errors Posted:**

| 02 | File Not Found |
| 03 | Path Not Found |
| 04 | Too Many Open Files |
| 05 | Access Denied |
| 32 | File Is Already Locked |
| 36 | Invalid Data File |
| 38 | Invalid Key File |
| 45 | Invalid File Name |
| 46 | Key Files Must Be Rebuilt |
| 47 | Invalid File Declaration |
| 52 | File Already Open |
| 57 | Invalid Memo File |
| 73 | Memo File is Missing |
| 75 | Invalid Field Type Descriptor |
| 79 | Unsupported Data Type In File |
| 88 | Invalid Key Length |
| 90 | File System Error |
| 92 | Build In Progress |

**Example:**

**ReadOnly    EQUATE(0)                           !Access mode equates**

**WriteOnly   EQUATE(1)**

**ReadWrite   EQUATE(2)**

**DenyAll     EQUATE(10h)**

**DenyWrite   EQUATE(20h)**

**DenyRead    EQUATE(30h)**

**DenyNone    EQUATE(40h)**

**Header   FILE,DRIVER('Clarion'),PRE(Hea)        !Declare header file layout**

**AcctKey   KEY(Hea:AcctNumber)**

**OrderKey  KEY(Hea:OrderNumber)**

**Record    RECORD**

**AcctNumber   LONG**

**OrderNumber  LONG**

**ShipToName   STRING(20)**

**ShipToAddr   STRING(20)**

**          END**

**         END**

**Detail    FILE,DRIVER('Clarion'),PRE(Dtl)        !Declare detail file layout**

**OrderKey   KEY(Dtl:OrderNumber)**

**Record     RECORD**

**OrderNumber LONG**

**Item        LONG**

**Quantity    SHORT**

**           END**

**          END**

**ViewOrder VIEW(Header),ORDER('+Hea:OrderNumber') !Declare VIEW structure**

**           PROJECT(Hea:OrderNumber)**

**           JOIN(Dtl:OrderKey,Hea:OrderNumber)    !Join Detail file**

**            PROJECT(Det:Item,Det:Quantity)**

**           END**

**          END**

** CODE**

** ****OPEN****(Names,ReadWrite+DenyNone)                  !Open fully shared access**

** ****OPEN****(Header)**

** ****OPEN****(Detail)**

** SET(Hea:AcctKey)                                !Set to primary file**

** ****OPEN****(ViewOrder)                                 !then Open view**

** SET(ViewOrder)                                  !or SET(view) after opening**

**                                                 !to use ORDER attribute**

** ****OPEN****(CustRpt)                                   !Open a report**

**Win1Proc PROCEDURE**

**Win1 WINDOW,ALRT(F10Key)**

**     END**

** CODE**

** ****OPEN****(Win1)                                      !Open the window**

** GlobalWindowReference &= Win1                   !Assign window reference to a **

**                                                 !global &WINDOW**

** ACCEPT**

**  IF EVENT() = EVENT:AlertKey**

**   START(Win2Proc)**

**  END**

** END**

**Win2Proc PROCEDURE**

**Win2 WINDOW**

**     END**

** CODE**

** ****OPEN****(Win2,GlobalWindowReference)                !Open Win2, "owned" by Win1**

** ACCEPT**

** END**

**See Also:**

[[share  open data file for shared access .htm|SHARE]]

[[close  close a data structure .htm|CLOSE]]

[[set  initiate sequential file processing .htm|SET]]

[[exists  return file existence .htm|EXISTS]]

[[file  declare a data file structure .htm|FILE]]

[[view  declare a  virtual  file .htm|VIEW]]

[[application  declare an mdi frame window .htm|APPLICATION]]

[[window  declare a dialog window .htm|WINDOW]]

[[report  declare a report structure .htm|REPORT]]

[[accept  the event processor .htm|ACCEPT]]

[[display  write use variables to screen .htm|DISPLAY]]

[[close  close a data structure .htm|CLOSE]]