Xref: utzoo comp.os.msdos.programmer:2044 comp.windows.ms.programmer:180 alt.msdos.programmer:2224 Path: utzoo!utgpu!cs.utexas.edu!hellgate.utah.edu!caen!sdd.hp.com!usc!apple!voder!pyramid!infmx!dragon2!lorena From: lorena@informix.com (Lon Anderson) Newsgroups: comp.os.msdos.programmer,comp.windows.ms.programmer,alt.msdos.programmer Subject: Re: DOS dir command - How does it work? Message-ID: Date: 20 Nov 90 17:24:33 GMT References: <1990Nov19.212134.6012@polyof.poly.edu> Sender: news@informix.com (Usenet News) Organization: Informix Software, Inc. Lines: 42 karl@polyof.poly.edu (Karl H. Muhlbach, Staff) writes: >Dear Fellow Netters: > I am writing a little utility but I need to get some >insight on something. I was wondering how DOS accomplishes the dir command. >Is it done via the DOS system calls or is it bios related? The reason I >ask is that part of my utility is to read a diskette and reference every >file on the diskette to see its file attributes (ie. size, date, >permissions, etc.). Unlike DOS I need to traverse the tree structure to >recursively reference every file. DOS will only indicate that a >particular file is a subdirectory and not change dir to reference the files >in it. I was considering using the ftw (file tree walk) system call but >was concerned about the max. open file limitation of 20. Could anyone shed >some light on this for me. This aspect and its speed performance are the >only things holding back the efficient completion of the utility. I have >it working with referencing the disk using the ftw call but there must be a >more efficient and quicker method. > I would greatly appreciate any help that might be sent my way. >Please EMail me any responses so that I may have a quicker turn around time >on an answer since I do not get much time to read news. Also, if your >response is to RTFM then fine, point me in the direction of a decent book >on DOS internals and I will RTFM! The books I have seen do not go into >stuff like this. > Thanks to all > in advance! > Karl M. >-- > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > Karl H. Muhlbach Email: karl@polyof.poly.edu > Voice: (516) 794-0142 > FAX: (516) 794-0142 The DOS dir command uses the FCB FindFirst and FindNext int 21h functions. Lon Anderson