_WRITEFILE
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The _WRITEFILE function 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 _READFILE$.
Syntax
- success% = _WRITEFILE(fileSpec$, contents$)
Parameters
- success% is an INTEGER return value, it shows whether the write operation was successful (-1) or not (0). Any file related ERROR may occur.
- To avoid errors you should use _PATHEXISTS before calling this function to make sure a used path exists.
- fileSpec$ is the name of the file to write as literal or variable STRING, if required inclusive a full or relative path.
- 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 a convenience function to wrap the following code sequence in one handy function:
fh = FREEFILE OPEN fileSpec$ FOR OUTPUT AS #fh: CLOSE #fh OPEN fileSpec$ FOR BINARY AS #fh PUT #fh, , contents$ CLOSE #fh |
Availability
none
v3.12.0
yes
yes
yes
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 doesn't exist." ELSE succ% = _WRITEFILE(dst$, buffer$) IF NOT succ% THEN CopyFile$ = "ERROR: Couldn't write destination file." END IF END IF END FUNCTION |
See also