### 3.1 `TMPDIR`—Directory for scratch files

When opening a file with `STATUS='SCRATCH'`, GNU Fortran tries to create the file in one of the potential directories by testing each directory in the order below.

1. The environment variable `TMPDIR`, if it exists.
2. On the MinGW target, the directory returned by the `GetTempPath` function. Alternatively, on the Cygwin target, the `TMP` and `TEMP` environment variables, if they exist, in that order.
3. The `P_tmpdir` macro if it is defined, otherwise the directory `/tmp`.