• d-bugmail puremagic.com (26/26) Oct 15 2007 http://d.puremagic.com/issues/show_bug.cgi?id=1583
• d-bugmail puremagic.com (44/44) Oct 19 2007 http://d.puremagic.com/issues/show_bug.cgi?id=1583

d-bugmail puremagic.com writes:

http://d.puremagic.com/issues/show_bug.cgi?id=1583

           Summary: std.cstream.CFile cannot be detached from FILE*
           Product: D
           Version: unspecified
          Platform: PC
        OS/Version: Windows
            Status: NEW
          Severity: normal
          Priority: P2
         Component: Phobos
        AssignedTo: bugzilla digitalmars.com
        ReportedBy: wbaxter gmail.com


The CFile class provides a nice wrapper around a C FILE*, but it provides NO
way of disconnecting itself from the file, and ultimately will try to close
whatever file you pass to it.

In particular I think the behavior of the file(FILE*) setter and the
constructor should be considered buggy.  They pretend the FILE is open even if
it is NULL.

If those methods actually checked for null, and didn't set the isopen flag in
those cases, then setting to null could be used as a way to detach the FILE.

As is, if you set the FILE* to null, there's no crash, but the CFile will
inevitably try to call fclose() on that null handle, which it should not, since
that will cause errno to get set.

Anyway, there should be a way to detach the file from the CFile.  I suggest
just using "set to null" to signal that, but I'd be happy with anything.


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d-bugmail puremagic.com writes:

http://d.puremagic.com/issues/show_bug.cgi?id=1583


thomas-dloop kuehne.cn changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         OS/Version|Windows                     |All




------- Comment #1 from thomas-dloop kuehne.cn  2007-10-19 12:23 -------
I use the following CFileEternal class. Compile with/without -version=kludge to 
see the difference.

# import std.stream : FileMode;
# import std.cstream : CFile;
# import std.c.stdio : FILE, fopen, ftell;
# import std.string : toStringz;
# import std.stdio : writefln;
#
# class CFileEternal : CFile{
#    this(FILE* cfile, FileMode mode, bool seekable = false) {
#       super(cfile, mode, seekable);
#    }
#
#    ~this(){
#       flush();
#       isopen = readable = writeable = seekable = false;
#    }
# }
#
# void main(char[][] args){
#    auto name = args[1];
#    FILE* f = fopen(toStringz(name), "w");
#
#    if(!f){
#       throw new Exception("failed to open " ~ name);
#    }
#
#    {
#       version(kludge){
#          scope cf = new CFileEternal(f, FileMode.Out);
#       }else{
#          scope cf = new CFile(f, FileMode.Out);
#       }
#    }
#
#    writefln("FILE \"%s\" has been closed: %s", name, -1 == ftell(f));
# }


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