[9fans] dirread() and dirreadall()

[9fans] dirread() and dirreadall()

[Ronald G Minnich]

As I read the man page for dirread(), it kind of implies that it returns 
an array of entries, and also implies that it returns one dir entry at a 
time.

"It [dirread] reads from fd and unpacks the data into an
    array of Dir structures whose address is returned in *buf (see stat(3)
    for the layout of a Dir)."


but


" by   contrast, dirread steps through a directory one read(3) at a time."

Anyways, FWIW, dirread reads in as much as it can, up to a limit of 
DIRMAX bytes, and fails if it can not allocate that much; and dirreadall 
reads in as much as it can, up to a limit of allocatable memory, and 
fails if it can not allocate that much.

For dirreadone(), I think, ya rolls yer own.

apologies if the error here is my inability to parse english.

ron

Re: [9fans] dirread() and dirreadall()

[Charles Forsyth]

> As I read the man page for dirread(), it kind of implies that it returns 
> an array of entries, and also implies that it returns one dir entry at a 
> time.


          The data returned by a read(2) on a directory is a set of
          complete directory entries ...

`a set'

          ... by contrast, dirread steps through a directory one
          read(2) at a time.

the result of dirread is the result of one read, which might be a set.

	  ... A successful read of a directory always returns an integral number of complete
          directory entries; dirread always returns complete Dir structures.
          Dirread and dirreadall return the number of Dir structures
          filled in buf.

this also suggests the possibility of more than one.

why did you want at most one at a time?

Re: [9fans] dirread() and dirreadall()

[Ronald G Minnich]

Charles Forsyth wrote:

> why did you want at most one at a time?
> 

well, it was my inability to parse english, after all.

I'm pulling one at a time since the server code I'm fooling with right 
now only returns one at a time. The Req struct in /sys/include/9p.h is a 
one-at-a-time struct, near as I can tell:

	Dir d;

So I can read lotsa dir entries, but return one at a time via the server 
code I'm using. Ah, unless I am not parsing something else correctly ...

I plan to stop doing things this way at some point, but for now I have 
other fish to fry. Not to mention, attend some remedial English classes.

ron

Re: [9fans] dirread() and dirreadall()

[Russ Cox]

> now only returns one at a time. The Req struct in /sys/include/9p.h is a
> one-at-a-time struct, near as I can tell:
>
>         Dir d;

That's for stat and wstat.  It's not for read.
Read (even read of a directory) uses count and data.
You can use dirread9p to make your life easier.
Filling in d shouldn't work at all!  This is all discussed
in 9p(2) in the Read section.

Russ

Re: [9fans] dirread() and dirreadall()

[Ronald G Minnich]

Russ Cox wrote:

> That's for stat and wstat.  It's not for read.
> Read (even read of a directory) uses count and data.
> You can use dirread9p to make your life easier.
> Filling in d shouldn't work at all!  This is all discussed
> in 9p(2) in the Read section.


thanks, now I remember why I like this list.

ron

Re: [9fans] dirread() and dirreadall()

[Ronald G Minnich]

Russ Cox wrote:

> That's for stat and wstat.  It's not for read.
> Read (even read of a directory) uses count and data.
> You can use dirread9p to make your life easier.
> Filling in d shouldn't work at all!  This is all discussed
> in 9p(2) in the Read section.

ah, I got it, I am using dirread9p after all, probably incorrectly.

thanks again

ron