Oracle linux c programs

6 Using Oracle Precompilers and the Oracle Call Interface

This chapter describes how to use Oracle precompilers and the Oracle Call Interface. It contains the following sections:

To use the demonstrations described in this chapter, install the Oracle Database Examples included on the Oracle Database 11 g Examples media.

6.1 Overview of Oracle Precompilers

Oracle precompilers are application development tools that are used to combine SQL statements for an Oracle Database with programs written in a high-level language. Oracle precompilers are compatible with ANSI SQL and are used to develop and open customized applications that run with Oracle Database or any other ANSI SQL database management system.

This section contains the following topics:

ORACLE_HOME in this section refers to ORACLE_HOME that is created while installing Oracle Database Client 11 g by using the Administrator Install type.

6.1.1 Precompiler Configuration Files

Configuration files for the Oracle precompilers are located in the $ORACLE_HOME/precomp/admin directory.

Table 6-1 lists the names of the configuration files for each precompiler.

Table 6-1 System Configuration Files for Oracle Precompilers

Pro*FORTRAN (AIX, HP-UX, and Solaris)

Object Type Translator

SQL*Module for Ada (AIX)

6.1.2 Relinking Precompiler Executables

Use the $ORACLE_HOME/precomp/lib/ins_precomp.mk make file to relink all precompiler executables. To manually relink a particular precompiler executable, enter the following command:

This command creates the new executable in the $ORACLE_HOME/precomp/lib directory, and then moves it to the $ORACLE_HOME/bin directory.

In the preceding example, replace executable with one of the product executables listed in Table 6-2.

Table 6-2 lists the executables for Oracle Precompilers.

Table 6-2 Executables for Oracle Precompilers

Product	Configuration File

Pro*C/C++ 32 bit (HP-UX and IBM: Linux on System z)

Pro*COBOL (AIX, HP-UX, and Solaris)

procob or rtsora

Pro*COBOL 32-bit (AIX, HP-UX, Solaris, and IBM: Linux on System z)

Pro*FORTRAN 32-bit (AIX, HP-UX, and Solaris)

SQL*Module for Ada (AIX)

6.1.3 Precompiler README Files

The README files describe changes made to the precompiler since the last release.

Table 6-3 lists the location of the precompiler README files.

Table 6-3 Location of Precompiler README Files

Product	Executable

6.1.4 Issues Common to All Precompilers

The following issues are common to all precompilers:

Uppercase to Lowercase Conversion

In languages other than C, the compiler converts an uppercase function or subprogram name to lowercase. This can cause a No such user exists error message. If you receive this error message, then verify that the case of the function or subprogram name in the option file matches the case used in the IAPXTB table.

Vendor Debugger Programs

Precompilers and vendor-supplied debuggers can be incompatible. Oracle does not guarantee that a program run using a debugger performs the same way when it is run without the debugger.

Value of IRECLEN and ORECLEN parameters

The IRECLEN and ORECLEN parameters do not have maximum values.

6.1.5 Static and Dynamic Linking

You can statically or dynamically link Oracle libraries with precompiler and OCI or OCCI applications. With static linking, the libraries and objects of the whole application are linked into a single executable program. As a result, application executables can become very large.

With dynamic linking, the executing code is partly stored in the executable program and partly stored in libraries that are linked dynamically by the application at run time. Libraries that are linked at run time are called dynamic or shared libraries. The benefits of dynamic linking are:

Reduced disk space requirements: Multiple applications or calls to the same application can use the same dynamic libraries.

Reduced main memory requirements: The same dynamic library image is loaded into main memory only once, and it can be shared by multiple application.

6.1.6 Client Shared and Static Libraries

The client shared and static libraries are located in $ORACLE_HOME/lib. If you use the Oracle-provided demo_ product .mk file to link an application, then the client shared library is linked by default.

If the shared library path environment variable setting does not include the directory that contains the client shared library, then you may see an error message similar to one of the following lines when starting an executable:

To avoid this error, set the shared library path environment variable to specify the appropriate directory. The following table shows sample settings for this environment variable name. If the platform supports both 32-bit and 64-bit applications, then ensure that you specify the correct directory, depending on the application that you want to run.

Precompiler	README File

Platform	Environment Variable	Sample Setting
AIX (32-bit applications)	LIBPATH	$ORACLE_HOME/lib
AIX (64-bit applications)	LIBPATH	$ORACLE_HOME/lib
HP-UX (32-bit applications)	SHLIB_PATH	$ORACLE_HOME/lib
HP-UX (64-bit applications) and Linux	LD_LIBRARY_PATH	$ORACLE_HOME/lib
Solaris (32-bit applications)	LD_LIBRARY_PATH	$ORACLE_HOME/lib
Solaris (64-bit applications)	LD_LIBRARY_PATH	$ORACLE_HOME/lib
IBM: Linux on System z (32-bit applications)	LD_LIBRARY_PATH	$ORACLE_HOME/lib
IBM: Linux on System z (64-bit applications)	LD_LIBRARY_PATH	$ORACLE_HOME/lib

The client shared library is created automatically during installation. If you must re-create it, then:

Quit all client applications that use the client shared library, including all Oracle client applications such as SQL*Plus and Oracle Recovery Manager.

Log in as the oracle user, and run the following command:

Nonthreaded Client Shared Library

The information in this section applies to HP-UX systems.

On HP-UX, you can use a non-threaded client shared library. However, you cannot use this library with any OCI application that uses or has a dependency on threads.

To use this library for applications that do not use threads, run the following command to build the OCI application for 32 and 64-bit:

6.2 Bit-Length Support for Client Applications

The following table identifies the bit lengths (31-bit, 32-bit, or 64-bit) supported for client applications:

Starting with Oracle Database 11 g Release 2 (11.2), 32-bit precompiler, 32-bit client executables, and libraries are not available in the 64-bit Oracle database installation. These are installed as part of the Oracle Database Client Installation.

Client Application Type	Supported Platforms
32-bit only	Linux x86
32-bit and 64-bit	AIX, HP-UX PA-RISC, Linux x86-64, SPARC, HP-UX Itanium, Solaris x86-64, and IBM: Linux on System z

The following table lists the 32-bit and 64-bit client shared libraries:

Starting with Oracle Database 11 g Release 2 (11.2), 32-bit and 64-bit Oracle Database Clients are installed in separate Oracle homes.

Platform	32-Bit (or 31-Bit) Client Shared Library	64-Bit Client Shared Library
AIX
HP-UX PA-RISC

Linux x86-64, Solaris, Solaris x86-64, and IBM: Linux on System z

To implement a mixed word-size installation:

Run the following command to generate the 32-bit and 64-bit client shared libraries:

Include the paths of the required 32-bit and 64-bit client shared libraries in one of the following environment variables, depending on the platform:

Platform	Environment Variable
AIX	LIBPATH
HP-UX (32-bit client applications)	SHLIB_PATH
HP-UX, Linux x86, Linux x86-64, Solaris, and IBM: Linux on System z	LD_LIBRARY_PATH

Building 32-Bit Pro*C and OCI Customer Applications

If the operating system supports both Pro*C and Oracle Call Interface (OCI) customer applications, then you can find more information about building Pro*C and OCI applications in the following files:

For Information About. . .	Refer to the Following Make Files. . .
Building Pro*C applications	$ORACLE_HOME/precomp/demo/proc/demo_proc.mk
Building OCI applications	$ORACLE_HOME/rdbms/demo/demo_rdbms.mk

6.3 Pro*C/C++ Precompiler

Before you use the Pro*C/C++ precompiler, verify that the correct version of the operating system compiler is properly installed.

Oracle Database Installation Guide for information about supported compiler versions

Pro*C/C++ Programmer’s Guide for information about the Pro*C/C++ precompiler and interface features

This section contains the following topics:

6.3.1 Pro*C/C++ Demonstration Programs

Demonstration programs are provided to show the features of the Pro*C/C++ precompiler. There are three types of demonstration programs: C, C++, and Object programs. All demonstration programs are located in the $ORACLE_HOME/precomp/demo/proc directory. By default, all programs are dynamically linked with the client shared library.

To run the demonstration programs, the programs require the demonstration tables created by the $ORACLE_HOME/sqlplus/demo/demobld.sql script to exist in the JONES schema with a password.

You must unlock the JONES account and set the password before creating the demonstrations.

Use the demo_proc.mk make file, which is located in the $ORACLE_HOME/precomp/demo/proc/ directory, to create the demonstration programs. For example, to precompile, compile, and link the sample1 demonstration program, run the following command:

On AIX systems, to ensure that the demonstration programs compile correctly, include the -r option of the make command in the following examples. For example:

To create all the C demonstration programs for Pro*C/C++, run the following command:

To create all the C++ demonstration programs for Pro*C/C++, run the following command:

To create all the Object demonstration programs for Pro*C/C++, run the following command:

Some demonstration programs require you to run a SQL script, located in the $ORACLE_HOME/precomp/demo/sql directory. If you do not run the script, then a message prompting you to run it is displayed.

To build a demonstration program and run the corresponding SQL script, include the make macro argument RUNSQL=run at the command line. For example, to create the sample9 demonstration program and run the required $ORACLE_HOME/precomp/demo/sql/sample9.sql script, run the following command:

To create all the Object demonstration programs and run all the required SQL scripts, run the following command:

6.3.2 Pro*C/C++ User Programs

You can use the $ORACLE_HOME/precomp/demo/proc/demo_proc.mk make file to create user programs. This make file builds either 32-bit or 64-bit user programs. You can also use the demo_proc32.mk make file to build 32-bit user programs. The following table shows the make files that you can use to build 32-bit and 64-bit user programs with Pro*C/C++:

Platform	64-bit Make File	32-Bit Make File
AIX, HP-UX, Linux x86-64, Solaris x86-64 and Solaris	demo_proc.mk	demo_proc32.mk
Linux x86	NA	demo_proc.mk

The make file for more information about creating user programs

On AIX systems, to ensure that the programs compile correctly, specify the -r option for the make command used in the following examples.

To create a program by using the demo_proc.mk make file, run a command similar to the following:

In this example:

target is the make file target that you want to use

objfilen is the object file to link the program

exename is the executable program

For example, to create the program myprog from the Pro*C/C++ source file myprog.pc , run one of the following commands, depending on the source and the type of executable that you want to create:

For C source dynamically linked with the client shared library, run the following command:

For C source statically linked with the client shared library, run the following command:

For C++ source dynamically linked with the client shared library, run the following command:

For C++ source statically linked with the client shared library, run the following command:

6.4 Pro*COBOL Precompiler

Table 6-4 shows the naming conventions for the Pro*COBOL precompiler.

Table 6-4 Pro*COBOL Naming Conventions

demo_procob.mk or demo_procob_32.mk

Pro*COBOL supports statically linked, dynamically linked, or dynamically loadable programs. Dynamically linked programs use the client shared library. Dynamically loadable programs use the rtsora executable located in the $ORACLE_HOME/bin directory.

This section contains the following topics:

6.4.1 Pro*COBOL Environment Variables

This section describes the environment variables required by Pro*COBOL:

6.4.1.1 Micro Focus Server Express COBOL Compiler

To use the Micro Focus Server Express COBOL compiler, you must set the COBDIR and PATH environment variables and the shared library path environment variable.

The «Client Shared and Static Libraries» section for information about the shared library path environment variable

Set the COBDIR environment variable to the directory where the compiler is installed. For example, if the compiler is installed in the /opt/lib/cobol directory, then run the following command:

Bourne, Bash, or Korn shell:

Set the PATH environment variable to include the $COBDIR/bin directory:

Bourne, Bash, or Korn shell:

Shared Library Path

Set the LIBPATH , LD_LIBRARY_PATH , or SHLIB_PATH environment variable to the directory where the compiler library is installed. For example, if the platform uses the LD_LIBRARY_PATH environment variable and the compiler library is installed in the $COBDIR/coblib directory, then run the following command:

Bourne, Bash, or Korn shell:

6.4.1.2 Acucorp ACUCOBOL-GT COBOL Compiler

To use the Acucorp ACUCOBOL-GT COBOL compiler, you must set the A_TERMCAP , A_TERM , PATH , and LD_LIBRARY_PATH environment variables. If the LD_LIBRARY_PATH environment variable setting does not include the correct directory, then an error message similar to the following is displayed when you compile or run a program:

A_TERMCAP and A_TERM

Set the A_TERMCAP environment variable to specify the location of the a_termcap file and set the A_TERM environment variable to specify a supported terminal from that file. For example:

Bourne, Bash, or Korn shell:

Set the PATH environment variable to include the /opt/COBOL/bin directory:

Bourne, Bash, or Korn shell:

On AIX, the LIBPATH variable is the LD_LIBRARY_PATH variable equivalent. You must use the LIBPATH variable on AIX instead of the LD_LIBRARY_PATH variable in the following commands.

Set the LD_LIBRARY_PATH environment variable to the directory where the compiler library is installed. For example, if the compiler library is installed in the /opt/COBOL/lib directory, then run the following command:

Bourne, Bash, or Korn shell:

6.4.2 Pro*COBOL Oracle Runtime System

Oracle provides its own complete run-time system, called rtsora , to run dynamically loadable Pro*COBOL programs. Use the rtsora run-time system instead of the cobrun run-time system to run dynamically loadable Pro*COBOL programs. If you attempt to run a Pro*COBOL program with cobrun , then an error message similar to the following is displayed:

6.4.3 Pro*COBOL Demonstration Programs

Demonstration programs are provided to show the features of the Pro*COBOL precompiler. The demonstration programs are located in the $ORACLE_HOME/precomp/demo/procob2 directory. By default, all programs are dynamically linked with the client shared library.

To run the demonstration programs, the programs require the demonstration tables created by the $ORACLE_HOME/sqlplus/demo/demobld.sql script to exist in the JONES schema with a password.

You must unlock the JONES account and set the password before creating the demonstrations.

Use the following make file to create the demonstration programs:

To precompile, compile, and link the sample1 demonstration program for Pro*COBOL, run the following command:

To create the Pro*COBOL demonstration programs, run the following command:

To create and run a dynamically loadable sample1.gnt program to be used with the rtsora run-time system, run the following command:

Some demonstration programs require you to run a SQL script, which is located in the $ORACLE_HOME/precomp/demo/sql directory. If you do not run the script, then a message requesting you to run it is displayed.

To build a demonstration program and run the corresponding SQL script, include the make macro argument RUNSQL=run in the command. For example, to create the sample9 demonstration program and run the required $ORACLE_HOME/precomp/demo/sql/sample9.sql script, run the following command:

To create the Pro*COBOL demonstration programs and run all required SQL scripts, run the following command:

6.4.4 Pro*COBOL User Programs

You can use the $ORACLE_HOME/precomp/demo/procob2/demo_procob.mk make file to create user programs. This make file builds either 32-bit or 64-bit user programs. You can also use the demo_procob.mk make file to build 32-bit (or 31-bit) user programs. The following table shows the make files that you can use to build 32-bit (or 31-bit) and 64-bit user programs with Pro*COBOL:

Item	Naming Convention

Platform	Make File
AIX, HP-UX, Linux x86-64, Solaris, IBM: Linux on System z, and Linux x86	demo_procob.mk

The make file for more information about creating user programs

To create a program using the demo_procob.mk make file, run a command similar to the following:

In this example:

target is the make file target that you want to use

cobfilen is the COBOL source file for the program

exename is the executable program

For example, to create the program myprog , run one of the following commands, depending on the source and type of executable that you want to create:

For COBOL source, dynamically linked with the client shared library, run the following command:

For COBOL source, statically linked, run the following command:

For COBOL source, dynamically loadable for use with rtsora , run the following command:

6.4.5 FORMAT Precompiler Option

The FORMAT precompiler option specifies the format of input lines for COBOL. If you specify the default value ANSI , then columns 1 to 6 contain an optional sequence number, column 7 indicates comments or continuation lines, paragraph names begin in columns 8 to 11, and statements begin in columns 12 to 72.

If you specify the value TERMINAL , then columns 1 to 6 are dropped, making column 7 the left most column.

6.5 Pro*FORTRAN Precompiler

Before you use the Pro*FORTRAN precompiler, verify that the correct version of the compiler is installed. This section contains the following topics:

Oracle Database Installation Guide for information about supported compiler versions

Pro*FORTRAN Supplement to the Oracle Precompilers Guide for information about the Pro*FORTRAN precompiler and interface features

6.5.1 Pro*FORTRAN Demonstration Programs

Demonstration programs are provided to show the features of the Pro*FORTRAN precompiler. All demonstration programs are located in the $ORACLE_HOME/precomp/demo/profor directory. By default, all programs are dynamically linked with the client shared library.

To run the demonstration programs, the demonstration tables created by the $ORACLE_HOME/sqlplus/demo/demobld.sql script must exist in the JONES schema with a password.

You must unlock the JONES account and set the password before creating the demonstrations.

To create the demonstration programs, use the demo_profor.mk make file, located in the $ORACLE_HOME/precomp/demo/profor directory. For example, to precompile, compile, and link the sample1 demonstration program, run the following command:

To create the Pro*FORTRAN demonstration programs, run the following command:

Some demonstration programs require you to run a SQL script that is located in the $ORACLE_HOME/precomp/demo/sql directory. If you do not run the script, then a message prompting you to run it is displayed.

To build a demonstration program and run the corresponding SQL script, include the make macro argument RUNSQL=run on the command line. For example, to create the sample11 demonstration program and run the required $ORACLE_HOME/precomp/demo/sql/sample11.sql script, run the following command:

To create the Pro*FORTRAN demonstration programs and run all the required SQL scripts, run the following command:

6.5.2 Pro*FORTRAN User Programs

You can use the $ORACLE_HOME/precomp/demo/profor/demo_profor.mk make file to create user programs. This make file builds either 32-bit or 64-bit user programs. You can also use the demo_profor_32.mk make file to build 32-bit user programs. The following table shows the make files that you can use to build 32-bit and 64-bit user programs with Pro*FORTRAN:

Platform	64-bit Make File	32-Bit Make File
AIX, HP-UX, and Solaris	demo_profor.mk	demo_profor_32.mk

The make file for more information about creating user programs

To create a program using the demo_proc.mk make file, run a command similar to the following:

In this example:

target is the make file target that you want to use

forfilen is the FORTRAN source for the program

exename is the executable program

For example, to create the program myprog from the Pro*FORTRAN source file myprog.pfo , run one of the following commands, depending on the type of executable that you want to create:

For an executable dynamically linked with the client shared library, run the following command:

For an executable statically linked with the client shared library, run the following command:

6.6 SQL*Module for ADA

The information in this section applies to the AIX platform.

Before using SQL*Module for Ada, verify that the correct version of the compiler is installed.

Oracle Database Installation Guide for information about required compiler versions

This section contains the following topics:

6.6.1 SQL*Module for Ada Demonstration Programs

Demonstration programs are provided to show the features of SQL*Module for Ada. All demonstration programs are located in the $ORACLE_HOME/precomp/demo/modada directory. By default, all programs are dynamically linked with the client shared library.

To run the ch1_drv demonstration program, the demonstration tables created by the $ORACLE_HOME/sqlplus/demo/demobld.sql script must exist in the JONES schema with a password.

You must unlock the JONES account and set the password before creating the demonstrations.

The demcalsp and demohost demonstration programs require that the sample college database exists in the MODTEST schema. You can use the appropriate make command to create the MODTEST schema and load the sample college database.

Run the following command to create the SQL*Module for Ada demonstration programs, run the necessary SQL scripts to create the MODTEST user, and create the sample college database:

To create a single demonstration program ( demohost ) and run the necessary SQL scripts to create the MODTEST user, and create the sample college database, run the following command:

To create the SQL*Module for Ada demonstration programs, without re-creating the sample college database, run the following command:

To create a single demonstration program ( demohost ), without re-creating the sample college database, run the following command:

To run the programs, you must define an Oracle Net connect string or alias named INST1_ALIAS that is used to connect to the database where the appropriate tables exist.

6.6.2 SQL*Module for Ada User Programs

You can use the $ORACLE_HOME/precomp/demo/modada/demo_modada.mk make file to create user programs. To create a user program with the demo_modada.mk make file, run a command similar to the following:

In this example:

modulen is a compiled Ada object

exename is the executable program

SQL_Module_arguments are the command-line arguments to be passed to the SQL*Module

6.7 OCI and OCCI

Before you use the Oracle Call Interface (OCI) or Oracle C++ Call Interface (OCCI), verify that the correct version of C or C++ is installed.

Oracle Database Installation Guide for information about supported compiler versions

This section contains the following topics:

6.7.1 OCI and OCCI Demonstration Programs

Demonstration programs that show the features of OCI and OCCI are provided with the software through the Oracle Database 11 g Examples media. There are two types of demonstration programs: C and C++. All demonstration programs are located in the $ORACLE_HOME/rdbms/demo directory. By default, all programs are dynamically linked with the client shared library.

To run the demonstration programs, the programs require the demonstration tables created by the $ORACLE_HOME/sqlplus/demo/demobld.sql script to exist in the JONES schema with a password. Some demonstration programs require specific .sql files to be run, as mentioned in the demonstration source files. OCCI demonstration programs require occidemo.sql to be run.

You must unlock the JONES account and set the password before creating the demonstrations.

Use the demo_rdbms.mk make file, which is located in the $ORACLE_HOME/rdbms/demo directory, to create the demonstration programs. For example, to compile and link the cdemo1 demonstration program, run the following command:

To create the C demonstration programs for OCI, run the following command:

To create the C++ demonstration programs for OCCI, run the following command:

6.7.2 OCI and OCCI User Programs

You can use the $ORACLE_HOME/rdbms/demo/demo_rdbms.mk make file to build user programs. This make file builds either 32-bit or 64-bit user programs. You can also use the demo_rdbms32.mk to build 32-bit user programs on a 64-bit operating system. The following table shows the make files that you can use to build 32-bit and 64-bit user programs with Pro*FORTRAN:

Platform	64-bit Make File	32-Bit Make File
AIX, HP-UX, Solaris, and Linux x86-64	demo_rdbms.mk	demo_rdbms32.mk
Linux x86	NA	demo_rdbms.mk

The make file for more information about building user programs

6.8 Oracle JDBC/OCI Programs with a 64-Bit Driver

The information in this section applies to AIX, HP-UX, Linux x86-64, and Solaris platforms.

You can use the instructions and make files described in this section to create JDBC/OCI user programs that use a 64-bit driver.

To run JDBC/OCI demonstration programs with a 64-bit driver:

Add $ORACLE_HOME/jdbc/lib/ojdbc5.jar to the start of the CLASSPATH environment variable value for each of the following files:

In the $ORACLE_HOME/jdbc/demo/samples/generic/Makefile file, modify the JAVA and JAVAC variables to specify the JDK location and the -d64 flag as follows:

Set the LD_LIBRARY_PATH_64 environment variable to include the $ORACLE_HOME/lib directory.

On AIX, the LIBPATH variable is the LD_LIBRARY_PATH_64 variable equivalent. You must use the LIBPATH variable on AIX instead of the LD_LIBRARY_PATH_64 variable.

6.9 Custom Make Files

Oracle recommends that you use the demo_ product .mk make files provided with the software to create user programs as described in the product-specific sections of this chapter. If you modify the provided make file or if you choose to use a custom-written make file, then remember that the following restrictions apply:

Do not modify the order of the Oracle libraries. Oracle libraries are included on the link line more than once so that all the symbols are resolved during linking.

Except for AIX, the order of the Oracle libraries is essential on all platforms for the following reasons:

Oracle libraries are mutually referential. For example, functions in library A call functions in library B, and functions in library B call functions in library A.

The HP-UX linkers are one-pass linkers. The AIX, Linux, and Solaris linkers are two-pass linkers.

Add the library to the beginning or to the end of the link line. Do not place user libraries between the Oracle libraries.

If you choose to use a make utility such as nmake or GNU make , then you must be aware of how macro and suffix processing differs from the make utility provided with the operating system. Oracle make files are tested and supported with the make utility.

Oracle library names and the contents of Oracle libraries are subject to change between releases. Always use the demo_ product .mk make file that ships with the current release as a guide to determine the required libraries.

6.10 Correcting Undefined Symbols

Oracle provides the symfind utility to assist you in locating a library or object file where a symbol is defined. When linking a program, undefined symbols are a common error that produce an error message similar to the following:

The error occurs when the linker cannot find a definition for a referenced symbol. If this error message is displayed, then verify that the library or object file containing the definition exists on the link line and that the linker is searching the correct directories for the file.

The following example shows the output from the symfind utility, which is used to locate the sqlcex symbol:

6.11 Multithreaded Applications

The Oracle libraries provided with this release are thread-safe, they support multithreaded applications.

6.12 Using Signal Handlers

Oracle Database uses signals for two-task communication. Signals are installed in a user process when the process connects to the database and are removed when it disconnects.

Table 6-5 describes the signals that Oracle Database uses for two-task communication.

Table 6-5 Signals for Two-Task Communication

The pipe driver uses SIGCLD, also referred to as SIGCHLD, when an Oracle process terminates. The operating system kernel sends a SIGCLD signal to the user process. The signal handler uses the wait() routine to determine if a server process died. The Oracle process does not catch SIGCLD; the user process catches it.

The pipe two-task driver uses SIGCONT to send out-of-band breaks from the user process to the Oracle process.

Two-task drivers use SIGINT to detect user interrupt requests. The Oracle process does not catch SIGINT; the user process catches it.

Oracle Net protocols use SIGIO to indicate incoming networking events.

The pipe driver uses SIGPIPE to detect end-of-file on the communications channel. When writing to the pipe, if no reading process exists, then a SIGPIPE signal is sent to the writing process. Both the Oracle process and the user process catch SIGPIPE. SIGCLD is similar to SIGPIPE, but it applies only to user processes, not to Oracle processes.

The pipe driver uses SIGTERM to signal interrupts from the user to the Oracle process. This occurs when the user presses the interrupt key, Ctrl+C . The user process does not catch SIGTERM; the Oracle process catches it.

Oracle Net TCP/IP drivers use SIGURG to send out-of-band breaks from the user process to the Oracle process.

The listed signals affect all precompiler applications. You can install one signal handler for SIGCLD (or SIGCHLD) and SIGPIPE when connected to the Oracle process. If you call the osnsui() routine to set it up, then you can have multiple signal handles for SIGINT. For SIGINT, use osnsui() and osncui() to register and delete signal-catching routines.

You can also install as many signal handlers as you want for other signals. If you are not connected to the Oracle process, then you can have multiple signal handlers.

Example 6-1 shows how to set up a signal routine and a catching routine .

Example 6-1 Signal Routine and Catching Routine

Example 6-2 shows how to use the osnsui() and the osncui() routines in an application program.

Example 6-2 osnsui() and osncui() Routine Template

6.13 XA Functionality

Oracle XA is the Oracle implementation of the X/Open Distributed Transaction Processing XA interface. The XA standard specifies a bidirectional interface between resource managers that provide access to shared resources within transactions, and between a transaction service that monitors and resolves transactions.

Oracle Call Interface has XA functionality. When building a TP-monitor XA application, ensure that the TP-monitor libraries (that define the symbols ax_reg and ax_unreg ) are placed in the link line before the Oracle client shared library. This link restriction is required when using the XA dynamic registration (Oracle XA switch xaoswd ).

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