Re: IFS Open Help... -- RPG400-L

hi Michael,

I've read that you've already solved your problem. Since it sounds likeyou're very new to this type of stuff, I'm going to go over your codewith a fine-toothed comb and tell you what I see:

I found in the archives that someone else needed to trim the FileName for
the openFile() routine that they were using, I'm wondering though, do I
need to have a trim about my FileNam on the FileNamP = %ADDR(FileNam) line?


Say this with me 3 times:

Never ever ever use %ADDR() or a pointer when you've codedOPTIONS(*STRING) on the prototype.Never ever ever use %ADDR() or a pointer when you've codedOPTIONS(*STRING) on the prototype.Never ever ever use %ADDR() or a pointer when you've codedOPTIONS(*STRING) on the prototype.

And yes, you do have to trim the spaces from the filename (if there areany spaces, that is.)

   // This is new to me, but I believe that I'm telling
   // this field to point to the address of FileNam
   FileNamP = %ADDR(FileNam);


Yes, that's what you're doing.  But you shouldn't be doing that!!

   // setup the OFlag to indicate that we want
   // this file to be write only and to truncate
   // left over data when the file already exists.
   // Again, I don't know how this works, but
   // O_WRONLY = write only, O_TRUNC = truncate.
   Oflag = O_WRONLY + O_TRUNC + O_TEXTDATA;

O_TRUNC means "clear the file before opening it". It's the IFSequivelent of the CLRPFM command.

A bigger problem is the way you're dealing with text data. You'vespecified O_TEXTDATA which means "my data is text". But, I usuallythink of it as meaning "I'd like you to translate my data from onecharacter set to another", because that's what it enables.

The problem, however, is that you've told it that your program's data isin code page 819 (which is a variant of ASCII). That's a rather strangeapproach, since most RPG programs have EBCDIC data, not ASCII data!

All I can conclude is that you were very confused, and trying things atrandom.

   // Open the file name requested.
   If open(FileNamP:Oflag:Omode:cp) = -1;
      perror(FileNamP);
      *In99 = *On;
      LeaveSR;
   EndIf;

It seems very strange to me that you'd use perror() from ILE C here. Doyou like your error messages to go to stderr? That's not the wayiSeries programmers typically do things!

Again, I want to remind you that you should NOT be using a pointer or%addr() when you have options(*string) specified. Your code SHOULD looklike this:


    If open(%trimr(FileNam):Oflag:Omode:cp) = -1;
       errMsg = %str(strerror(errno));
       // display errMsg to user, or write to log, or whatever...
       *In99 = *On;
       LeaveSR;
    EndIf;

I see three important concepts that you should read about, andunderstand, before continuing:


a) How options(*string) works.  How to use it properly.

b) How to enable translation of text data in IFS files. (and, related...why you should be using a CCSID instead of a code page. If you'rerunning V5R2 or later, you should also learn about O_TEXT_CREAT.)


c) How error message handling works with unix-type APIs.