How do you read and write to temporary files in BBC BASIC for Windows?
We shall create one temporary file in program one, which will write a short message and the current time into a text file. Program two will read the text from this file and display on the screen.
Code for Program one:
REM this program writes a
REM temporary text file
text1$ = "Hello, this file was created by program 1 @"
text2$ = TIME$
REM create the file
PRINT "writing temp file"
PROC_createTempFile( "mytemp.tmp", text1$+text2$ )
PRINT "done"
STOP
DEFPROC_createTempFile( filename$, text$ )
REM writes the text into the temp file whose
REM filename is passed in filename$
LOCAL file%
file% = OPENOUT( @tmp$+filename$ )
PRINT#file%, text$
CLOSE#file%
ENDPROC
Code for Program two:
REM this program reads from a
REM temporary text file
PRINT "looking for the text file."
text$ = FN_readTempFile( "mytemp.tmp" )
PRINT "file contains:"
PRINT text$
STOP
DEFFN_readTempFile( filename$ )
REM reads the temporary file and returns the text
REM as a string
LOCAL file%, temp$
file% = OPENIN( @tmp$+filename$ )
INPUT#file%, temp$
CLOSE#file%
= temp$
If you need to navigate through Windows file explorer to find the files yourself then you should find that these programs are reading and writing to a folder located at %USERPROFILE%\AppData\Local\Temp
It would certainly be an advantage to delete the file after it has been used. Also, it would be better if we could deal with unexpected behaviour and variable sized data lengths.
I will look at some improvements to this code in the next post.