# IBM System SSL Environment Variables on z/OS

There are some System SSL environment variables related to tracing and debug messages which must be specified before the EMS library is loaded.

Note: Tracing is supported only on z/OS systems.

These environment variables are discussed in the IBM System Secure Sockets Layer programming guide, but a short summary is provided here:

- Set the file name (USS only) for raw trace records:
  - `GSK_TRACE_FILE <trace file name>`
  - `GSK_TRACE <mask>` — specify `255` to trace everything

    These two values enable detailed tracing of all GSK calls to a file. The file may subsequently be formatted for viewing using the `gsktrace` command.

- `GSK_HW_CRYPTO <crypto mask>` — `65535` to enalble all, `0` to disable all hardware cryptographic functions.
- `GSK_SSL_HW_DETECT_MESSAGE` — if set, causes brief messages regarding the state of the installed hardware to be written to stdout when the application is started.

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