At least with some environment variables and some operating systems, the variables are only used by the OS at process start time. This means that setting the environment variables after the start of your process does not help the current instance of your process. One approach to circumvent is to set up the environment within the first instance of your process and then to relaunch the process via exec. See for some examples:

In reply to Re: Testing a library that accesses an Oracle Database by Corion
in thread Testing a library that accesses an Oracle Database by docdurdee

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