_WRITEFILE

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The _WRITEFILE statement writes a string into a new file, overwriting an existing file of the same name. It does OPEN, PUT and CLOSE the file in one run. It's the counterpart to the _READFILE$ function.


Syntax

_WRITEFILE fileSpec$, contents$


Parameters

  • fileSpec$ is the name of the file to write as literal or variable STRING, if required inclusive a full or relative path.
    • To avoid errors you should use _DIREXISTS before using this statement to make sure a desired path exists.
  • contents$ is the literal or variable STRING which its contents shall be written into the file.


Description

  • Sometimes you may be in need to quickly dump a huge amount of data into a file without much fuss, e.g. the results of the pack/unpack functions _DEFLATE$ and _INFLATE$ or when copying a file in conjunction with the _READFILE$ function.
  • In earlier versions of QB64(PE) you had to implement that saving process manually all the time or create a reusable custom FUNCTION for it.
  • Now _WRITEFILE will simplify this, it's mainly for convenience to wrap the following code sequence into one handy statement:
fh = FREEFILE
OPEN fileSpec$ FOR OUTPUT AS #fh: CLOSE #fh
OPEN fileSpec$ FOR BINARY AS #fh
PUT #fh, , contents$
CLOSE #fh


Availability


Examples

Example
Implementing a simple file copy routine using _READFILE$ and _WRITEFILE.
s$ = "Makefile"
d$ = "Makefile - Copy"

r$ = CopyFile$(s$, d$)

IF r$ = "" THEN
    PRINT "Sucessfully copied '"; s$; "' to '"; d$; "'."
ELSE
    PRINT r$
END IF

END

FUNCTION CopyFile$ (src$, dst$)
    CopyFile$ = "" 'empty = success, otherwise error message
    buffer$ = _READFILE$(src$)
    IF buffer$ = "" AND _FILEEXISTS(src$) = 0 THEN
        CopyFile$ = "ERROR: Source file not found."
    ELSE
        slp% = _INSTRREV(dst$, "\")
        IF slp% = 0 THEN slp% = _INSTRREV(dst$, "/")
        IF slp% > 0 THEN
            IF NOT _DIREXISTS(LEFT$(dst$, slp% - 1)) THEN
                CopyFile$ = "ERROR: Destination path not found."
                EXIT FUNCTION
            END IF
        END IF
        _WRITEFILE dst$, buffer$
    END IF
END FUNCTION
Example by RhoSigma


See also



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