Output to a File

Writing to a file is pretty much the same as reading from one. You need to open the file first. This time you should use the OPEN function to indicate that you will do output to the file. For example:

    (setq fp (open "test.dat" :direction :output :if-exists :supersede))

Evaluating this expression will open the file "test.dat" for output. If the file already exists, its current contents will be discarded. If it doesn't already exist, it will be created. In any case, a FILE-STREAM object will be returned by the OPEN function. This file object will be assigned to the "fp" variable.

It is now possible to write to this file by supplying the value of the "fp" variable as the optional "stream" parameter in the PRINT function.

    (print "Hello there" fp)

Evaluating this expression will result in the string "Hello there" being written to the file "test.dat". More data can be written to the file using the same technique.

Once you are done writing to the file, you should close it. Closing an output file is just like closing an input file.

    (close fp)

Evaluating this expression will close the output file and make it permanent.

XLISP-PLUS - Version 2.1g - Tom Almy tom.almy@tek.com - 18 JUL 94

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