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Using Pro*C/C++

This chapter explains how to create and precompile a project. It also describes the Pro*C/C++ graphical user interface, from which you execute commands with Windows menus and icons or with keyboard equivalents, and using Pro*C/C++ at the command line. Specific topics discussed are:

• Using the Graphical User Interface

• Creating and Precompiling a Pro*C/C++ Project

• Using Pro*C/C++ at the Command Line

• Header Files

• Library Files

• Building Multi-Threaded Applications

• Precompiler Options

• Using Pro*C/C++ with the Oracle XA Library

  Note: See the Pro*C/C++ Precompiler Programmer's Guide for additional information about Pro*C/C++.

Using the Graphical User Interface

Before you follow the instructions for creating and precompiling a Pro*C/C++ project, you should familiarize yourself with the basic commands, dialog boxes, menus, and buttons of the Pro*C/C++ graphical user interface.

Starting Pro*C/C++ Graphical Interface

To start the graphical user interface, choose Start > Programs > Oracle - HOME_NAME > Application Development > Pro C_C++.

The Pro*C/C++ precompile environment contains five elements noted in the following illustration:

Text description of the illustration ch2a.gif.

Title Bar

The title bar displays the name of the Pro*C/C++ project. If you have not assigned a name to the current project, the word "Untitled" appears instead.

Menu Bar

The menu bar contains the following menus:

Menu	Description
File	Contains commands to create a new Pro*C/C++ project, open an existing Pro*C/C++ project, save the active Pro*C/C++ project under the same name or under a different name, specify a connect string to an Oracle database, precompile a Pro*C/C++ project, and exit the application.
Edit	Contains commands to add files to a Pro*C/C++ project, delete files from a Pro*C/C++ project, and display or change precompiler options.
Preferences	Contains commands to set the default file extension of output files.
Help	Contains the About Pro*C/C++ command, which displays the version number of the application and copyright information.

Toolbar

The toolbar enables you to execute commands by clicking a button:

Text description of the illustration ch27.gif.

Button	Description
New	Create a new Pro*C/C++ project
Open	Open an existing Pro*C/C++ project
Save	Save the active Pro*C/C++ project under the same name
Add	Add files to a Pro*C/C++ project
Delete	Delete files from a Pro*C/C++ project
Options	Display or change precompiler options
Precompile	Precompile a Pro*C/C++ project

Information Pane

The information pane consists of four elements noted in the following illustration:

Text description of the illustration ch29.gif.

Element	Description
Precompilation Status Bar	Indicates whether the precompilation for a file was successful or unsuccessful.
Input File	Shows the files of a Pro*C/C++ project to be precompiled.
Output File	Shows the output files of a Pro*C/C++ project after precompilation.
Options	Displays precompile options that are different from the default options.

Look for one of the three status icons in the precompilation status bar after the precompile process is complete.

• A green check indicates that the file precompiled successfully.

• A yellow check indicates that the file precompiled successfully, but there are one or more warnings.

• A red X indicates that the file did not precompile successfully.

Double clicking a status icon opens the Precompilation Status dialog box. This dialog box provides detailed information on the reason for a warning or failure.

Status Bar

The status bar at the bottom of the window displays information about the progress of a precompilation. The status bar also identifies the purpose of a toolbar button or menu command when you place the mouse pointer over the toolbar button or menu command.

Creating and Precompiling a Pro*C/C++ Project

This section describes the steps involved in creating and precompiling a Pro*C/C++ project. After starting the Pro*C/C++ application, perform the following steps:

• Opening a Project

• Setting the Default Extension of Output Files

• Changing the Name of an Existing Input or Output File

• Adding Files to the Project

• Deleting Files from the Project

• Setting the Precompiler Options

• Specifying Database Connection Information

• Precompiling a Pro*C/C++ Project

• Checking the Results

• Fixing Errors

• Exiting Pro*C/C++

Opening a Project

Pro*C/C++ opens only one project at a time. A project consists of one or more precompilable files. Project files have an extension of .pre.

• To create a new project, choose File > New Project.

• To open an existing project, choose File > Open Project.

Setting the Default Extension of Output Files

Use the Preferences menu to determine the default extension of the output files.

Text description of the illustration prefs.gif.

This setting only affects input files that you add later. An existing output file name will not change. However, you can change an existing output file name by double-clicking the output file and entering a new name.

• If you select Default Output C File Name, the default extension of the output files is .c.

• If you select Default Output C++ File Name, the default extension of the output files is .cpp.

• If you deselect both Default Output C File Name and Default Output C++ File Name, the Output File dialog box appears when you add an output file.
  • Enter an output file name for the file selected. After you select or enter a file name, it appears in the Output File area of the information pane.

Changing the Name of an Existing Input or Output File

To change the name of an existing input or output file:

1. Double-click the file name in the Input File or Output File area of the information pane. The Input File or Output File dialog box appears.

   
   

   Text description of the illustration output.gif.

2. Replace the old file name with the new file name.

3. Click Open.

Adding Files to the Project

To add files to the project:

1. Choose Edit > Add. The Input File dialog box appears.

   
   

   Text description of the illustration input.gif.

2. Select one or more .pc files. Use the Ctrl key and the mouse to select files that are not adjacent.

3. Click Open. The selected files appear in the information pane.

Deleting Files from the Project

If you need to, you can easily delete one or more files from the project.

To delete files from the project:

1. Highlight the file(s) in the information pane.

2. Choose Edit > Delete.

3. Click Yes.

Setting the Precompiler Options

The Precompiler options enable you to control how resources are used, how errors are reported, how input and output are formatted, and how cursors are managed.

To set the precompile options:

1. Select one or more files in the Input File list.

2. Choose Edit > Options. The Options dialog box appears.

   
   

   Text description of the illustration options.gif.

   Default options are in effect for all newly added files. When you change an option's default setting, a description of the change appears in the Option String edit field at the bottom of the Options dialog box and in the Options area of the information pane. For additional information on options, see "Precompiler Options".

3. To change the format of the output list file that the precompiler writes to disk, click the Listing / Errors button. The Listing/Errors dialog box appears.

   
   

   Text description of the illustration listerr.gif.

   The settings include the type of error information generated and the name of the list file.

4. After you set the options in the Options dialog box, click OK.

Specifying Database Connection Information

If you selected semantics or full for the SQL Check option in the Options dialog box, you may need to specify database connection information to the Oracle database. You do not need to connect to the Oracle database if every table referenced in a data manipulation statement or PL/SQL block is defined in a DECLARE TABLE statement.

To specify database connection information:

1. Choose File > Connect. The Connect dialog box appears.

   
   

   Text description of the illustration connect.gif.

2. Use this dialog box to specify database connection information prior to precompiling. No database connection is performed at this time. Only one set of database connection information can be specified for all files requiring semantic or full SQLCHECKing.

3. The Connect dialog box appears automatically at precompile time if you have not previously responded. Enter the user name, the password, and the network service name (database alias). The network service name is not required for a local database.

4. If you want to save the connection information between Pro*C/C++ sessions, select the Save Connect String to Disk check box. If you do not select the check box, you must enter this information each time you precompile.

5. Click OK.

Precompiling a Pro*C/C++ Project

You can precompile any number of files in the Input File list.

To precompile:

1. Select one or more files in the Input File list. You can use the Ctrl button to highlight files that are not adjacent to each other (for example, the first and third files in a list).

2. Choose File > Precompile.

   When precompiling is completed, the message in the dialog box indicates "Precompiling Finished!", and the Cancel button changes to OK.

3. Click OK.

   Note: Although Cancel does not interrupt the precompile for a file already in process, it does halt the precompile chain for remaining files.

Checking the Results

Precompiling can result in success, success with warning(s), or failure. When precompiling is finished, check the precompilation status bar.

• A green check indicates that the file compiled successfully.

• A yellow check indicates that the file compiled successfully, but there are one or more warnings.

• A red X indicates that the file did not compile successfully.

Fixing Errors

If you see a yellow check or a red X, double-click the icon in status bar. The Precompilation Status dialog box appears. This dialog box lists warning messages or reasons why the precompilation failed. For example:

Text description of the illustration error.gif.

Switch to your development environment to fix the problem(s). After you correct the errors, precompile again.

Note: If you receive a PCC-S-02014 error (syntax error at line num, column colnam, file name), do the following: Copy the batch files mod_incl.bat and add_newl.bat from the oracle_base\oracle_home\precomp\misc\proc directory to the directory that contains the problematic INCLUDE file. Run mod_incl.bat.

Exiting Pro*C/C++

To exit Pro*C/C++, choose File > Exit. If your project changed in any way, you are prompted to save it.

Suggestion: If you want to keep an original file, as well as a version of the file with your changes, choose the Save As command. The Save command overwrites the previous version.

Using Pro*C/C++ at the Command Line

To precompile a file at the command line, enter the following command:

C:\> proc iname=filename.pc

where filename.pc is the name of the file. If the file is not in your current working directory, include the file's full path after the INAME argument.

Pro*C/C++ generates filename.c, which can be compiled by your C compiler.

Header Files

The oracle_base\oracle_home\precomp\public directory contains the Pro*C/C++ header files.

See Also: See the Pro*C/C++ Precompiler Programmer's Guide for more information about oraca.h, sqlca.h, and sqlda.h.

Header File	Description
oraca.h	Contains the Oracle Communications Area (ORACA), which helps you to diagnose runtime errors and to monitor your program's use of various Oracle8 resources.
sql2oci.h	Contains SQLLIB functions that enable the Oracle Call Interface (OCI) environment handle and OCI service context to be obtained in a Pro*C/C++ application.
sqlapr.h	Contains ANSI prototypes for externalized functions that can be used in conjunction with OCI.
sqlca.h	Contains the SQL Communications Area (SQLCA), which helps you to diagnose runtime errors. The SQLCA is updated after every executable SQL statement.
sqlcpr.h	Contains platform-specific ANSI prototypes for SQLLIB functions that are generated by Pro*C/C++. By default, Pro*C/C++ does not support full-function prototyping of SQL programming calls. If you need this feature, include sqlcpr.h before any EXEC SQL statements in your application source file.
sqlda.h	Contains the SQL Descriptor Area (SQLDA), which is a data structure required for programs that use dynamic SQL Method 4.
sqlkpr.h	Contains K&R prototypes for externalized functions that can be used in conjunction with OCI.
sqlproto.h	The sqlproto.h header file was obsoleted in Pro*C/C++ release 8.0.3. Use sqlcpr.h instead of sqlproto.h. However, applications that were built using sqlproto.h can be created without modification: a dummy sqlproto.h file that includes sqlcpr.h has been provided in the oracle_base\oracle_home\precomp\public directory.

Library Files

The oracle_base\oracle_home\precomp\lib\msvc directory contains the library file that you use when linking Pro*C/C++ applications. The library file is called orasql8.lib.

Pro*C/C++ application program interface (API) calls are implemented in DLL files provided with your Pro*C/C++ software. To use the DLLs, you must link your application with the import libraries (.lib files) that correspond to the Pro*C/C++ DLLs. Also, you must ensure that the DLL files are installed on the computer that is running your Pro*C/C++ application.

Microsoft provides you with three libraries: libc.lib, libcmt.lib, and msvcrt.lib. The Oracle DLLs use the msvcrt.lib runtime library. You must link with msvcrt.lib rather than the other two Microsoft libraries.

Building Multi-Threaded Applications

Build multi-threaded applications if you are planning to perform concurrent database operations.

Windows NT and Windows 95/98 schedule and allocate threads belonging to processes. A thread is a path of a program's execution. It consists of a kernel stack, the state of the CPU registers, a thread environment block, and a users stack. Each thread shares the resources of a process. Multi-threaded applications use the resources of a process to coordinate the activities of individual threads.

When building a multi-threaded application, make sure that your C/C++ code is reentrant. This means that access to static or global data must be restricted to one thread at a time. If you mix multi-threaded and non-reentrant functions, one thread can modify information that is required by another thread.

The Pro*C/C++ precompiler automatically creates variables on the local stack of the thread. This ensures that each thread using the Pro*C/C++ function has access to a unique set of variables and is reentrant.

See Also: See the Pro*C/C++ Precompiler Programmer's Guide for additional information on how to write multi-threaded applications with Pro*C/C++.

Precompiler Options

This section highlights issues related to Pro*C/C++ for Windows platforms.

See Also: See the "Precompiler Options" chapter of the Pro*C/C++ Precompiler Programmer's Guide for more information on the precompiler options.

Configuration File

A configuration file is a text file that contains precompiler options.

For this release, the system configuration file is called pcscfg.cfg. This file is located in the oracle_base\oracle_home\precomp\admin directory.

CODE

The CODE option has a default setting of ANSI_C. Pro*C/C++ for other operating systems may have a default setting of KR_C.

DBMS

DBMS=V6_CHAR is not supported when using CHAR_MAP=VARCHAR2. Instead, use DBMS=V7.

INCLUDE

For the Pro*C/C++ graphical user interface, use the Include Directories field of the Options dialog box to enter INCLUDE path directories. If you want to enter more than one path, separate each path with a semicolon, but do not insert a space after the semicolon. This causes a separate "INCLUDE=" string to appear in front of each directory.

For sample programs that precompile with PARSE=PARTIAL or PARSE=FULL, an include path of c:\program files\devstudio\vc\include has been added. If Microsoft Visual C++ has been installed in a different location, modify the Include Directories field accordingly for the sample programs to precompile correctly.

PARSE

The PARSE option has a default setting of NONE. Pro*C/C++ for other operating systems may have a default setting of FULL.

Using Pro*C/C++ with the Oracle XA Library

The XA Application Program Interface (API) is typically used to enable an Oracle database to interact with a transaction processing (TP) monitor, such as:

• BEA Tuxedo

• IBM Transarc Encina

• IBM CICS

You can also use TP monitor statements in your client programs. The use of the XA API is also supported from both Pro*C/C++ and OCI.

The Oracle XA Library is automatically installed as part of Oracle8i Enterprise Edition. The following components are created in your Oracle home directory:

Component	Location
oraxa8.lib	oracle_base\oracle_home\rdbms\xa
xa.h	oracle_base\oracle_home\rdbms\xa

Compiling and Linking a Pro*C/C++ Program with XA

To compile and link a Pro*C/C++ program with XA:

1. Precompile filename.pc using Pro*C/C++ to generate filename.c.

2. Compile filename.c, making sure to include oracle_base\oracle_home\rdbms\xa in your path.

3. Link filename.obj with the following libraries:

   Library	Location
   oraxa8.lib	oracle_base\oracle_home\rdbms\xa
   oci.lib	oracle_base\oracle_home\oci\lib\msvc
   orasql8.lib	oracle_base\oracle_home\precomp\lib\msvc

4. Run filename.exe.

XA Dynamic Registration

Oracle supports the use of XA dynamic registration. XA dynamic registration improves the performance of applications that interface with XA-compliant TP monitors.

For TP monitors to use XA dynamic registration with an Oracle database on Windows NT, you must add either an environmental variable or a registry variable to the Windows NT computer on which your TP monitor is running. See either of the following sections for instructions:

• Adding an Environmental Variable for the Current Session

• Adding a Registry Variable for All Sessions

Adding an Environmental Variable for the Current Session

Adding an environmental variable at the MS-DOS command prompt affects only the current MS-DOS session.

To add an environmental variable for the current session:

1. Go to the computer where your TP monitor is installed.

2. Enter the following at the MS-DOS command prompt:

   C:\> set ORA_XA_REG_DLL = vendor.dll
   

   where vendor.dll is the TP monitor DLL provided by your vendor.

Adding a Registry Variable for All Sessions

Adding a registry variable affects all sessions on your Windows NT computer. This is useful for computers where only one TP monitor is running.

To add a registry variable for all sessions:

1. Go to the computer where your TP monitor is installed.

2. Enter the following at the MS-DOS command prompt:

   C:\> regedit
   

   The Registry Editor window appears.

3. Go to HKEY_LOCAL_MACHINE\SOFTWARE\ORACLE.

4. Choose the Add Value option in the Edit menu.

   The Add Value dialog box appears.

5. Enter ORA_XA_REG_DLL in the Value Name field.

6. Select REG_EXPAND_SZ from the Data Type drop-down list box.

7. Click OK.

   The String Editor dialog box appears.

8. Enter vendor.dll in the String field, where vendor.dll is the TP monitor DLL provided by your vendor.

9. Click OK.

   The Registry Editor adds the parameter.

10. Choose Exit from the Registry menu.

    The registry exits.

XA and TP Monitor Information

Refer to the following for more information about XA and TP monitors:

• Distributed TP: The XA Specification published by X/Open (now part of OpenGroup). See the web site at:

  http://www.opengroup.org/publications/catalog/tp.htm

• Transaction Processing XPG4 X/Open CAE Specification XO/CAE/91/300 or C193 2/92

• X/Open Company, Ltd., 1010 El Camino Real, Suite 380, Menlo Park, CA 94025, U.S.A.

• Your specific TP monitor documentation

  See Also: For more information about the Oracle XA Library and using XA dynamic registration, see Oracle8i Application Developer's Guide - Fundamentals.