OpenExtensions for z/VM "Q"s and "A"s

Question: Can I use a ddname for an HFS file in an application?

Answer: Instead of using data set names or pathnames in an application, you can use a ddname; then with a FILEDEF command you associate a specific file with that ddname.

You have a choice of two methods for accessing data sets and files in an application:

• The OPEN macro
• The fopen() function

The OPEN Macro

The OPEN macro can open a BFS file pointed to by a PATHDEF statement.

The fopen() Function

The fopen() function recognizes and handles the difference between a ddname associated with a record file or a byte file. For example:

fopen("dd:FRED", "r+")

takes the ddname FRED, determines if FRED refers to a ddname for a CMS record file, a FILEDEF, or a byte file, and opens it. Once a file is opened, fread() and fwrite() can access the data.

---

For more questions and answers, go to our archive of questions and answers.