SQL & PL/SQL

Hello, I need to call a PL/SQL stored procedure from a C program.
Something like this sample program provided by Oracle -

main()
*{*
int i;
EXEC SQL BEGIN DECLARE SECTION;
*/* Define type for null-terminated strings. */*
EXEC SQL TYPE asciz IS STRING(20);
asciz username[20];
asciz password[20];
int dept_no; / which department to query */*
char emp_name[10][21];
char job[10][21];
EXEC SQL VAR emp_name is STRING (21);
EXEC SQL VAR job is STRING (21);
float salary[10];
int done_flag;
int array_size;
int num_ret; / number of rows returned */*
int SQLCODE;
EXEC SQL END DECLARE SECTION;

*/* Connect to Oracle. */*
strcpy(username, "SCOTT");
strcpy(password, "TIGER");

EXEC SQL WHENEVER SQLERROR DO sqlerror();

EXEC SQL CONNECT :username IDENTIFIED BY :password;

printf("Enter department number: ");
scanf("%d", &dept_no);
fflush(stdin);

*/* Set the array size. */*
array_size = 10;
done_flag = 0;
num_ret = 0;

*/* Array fetch loop - ends when NOT FOUND becomes true. */*
EXEC SQL EXECUTE
BEGIN personnel.get_employees
*(:dept_no, :array_size, :num_ret, :done_flag,*
*:emp_name, :job, :salary);*
END;
END-EXEC;

*}*

The question is - how is the Stored procedure get_employees declared ? Or more specifically, how is the salary parameter declared in get_employees ? Any help is highly appreciated.