R: Temporary files

rasterTmpFile {raster} | R Documentation

## Temporary files

### Description

Functions in the raster package create temporary files if the values of an output Raster* object cannot be stored in memory (RAM). This can happen when no filename is provided to a function and in functions where you cannot provide a filename (e.g. when using 'raster algebra').

Temporary files are automatically removed at the start of each session. During a session you can use `showTmpFiles` to see what is there and `removeTmpFiles` to delete all the temporary files. `rasterTmpFile` returns a temporary filename. These can be useful when developing your own functions. These filenames consist of `prefix_date_time_pid_rn` where `pid` is the process id returned by `Sys.getpid` and `rn` is a 5 digit random number. This should make tempfiles unique if created at different times and also when created in parallel processes (different pid) that use `set.seed` and call rasterTmpFile at the same time. It is possible, however, to create overlapping names (see the examples), which is undesirable and can be avoided by setting the prefix argument.

### Usage

    rasterTmpFile(prefix='r_tmp_')
    showTmpFiles()
    removeTmpFiles(h=24)

### Arguments

`prefix` | Character. Prefix to the filename (which will be followed by 10 random numbers)
`h` | Numeric. The minimum age of the files in number of hours (younger files are not deleted)

### Value

`rasterTmpFile` returns a valid file name

`showTmpFiles` returns the names (.grd only) of the files in the temp directory

`removeTmpFiles` returns nothing

### See Also

`rasterOptions`, `tempfile`

### Examples

    ## Not run:
    rasterTmpFile('mytemp_')
    showTmpFiles()
    removeTmpFiles(h=24)

    ## End(Not run)

[Package raster version 3.0-7 Index]