Executing external C programs from PL/SQL

Let's us walk through an illustration on how to execute an external procedure, written in the C language, in the Oracle Database.

• Step 1: Creating and compiling the C program.

  The following C program (GetMax.c) finds the maximum of the two number values:

  #include <stdio.h>
  
  /* Define the function returning the max between two numbers */
  int GetMax(int num1, int num2)
  {
     /* local variable declaration */
     int result;
  
     if (num1 > num2)
        result = num1;
     else
        result = num2;
  
     return result;
  }

  Compile the program by using a C compiler.

  sh-4.3# gcc -c GetMax.c

• Step 2: Generating the DLL and creating the library object in the Oracle Database.

  We will now generate the DLL for the C program:

  sh-4.3# gcc -shared GetMax.c -o GetMax.dll

  • The library location

    The default paths searched by the extproc process for loading the required library are $ORACLE_HOME/bin and $ORACLE_HOME/lib. For testing purposes, we will continue with the defaults....