From: "Masaki Sawanobori" <masaki@zentek.com>
To: <ecos-discuss@sourceware.cygnus.com>
Subject: [ECOS] I/O driver lookup handler: read/write mode
Date: Tue, 30 Nov 1999 02:59:00 -0000 [thread overview]
Message-ID: <062c01bf3b22$2a8be000$437201aa@atlantis7> (raw)
Hello,
I am implementing a simple flash memory file system in the framework of eCos
I/O device driver model and C language libc stdio module so the user can
access a file using fopen() as follows.
FILE *fp = fopen("/dev/flash0/filename", "r");
FILE *fp = fopen("/flash0/filename", "w");
The problem is that the second paramter(read/write mode) of fopen() is not
passed down to a "lookup" device driver handler(via the cyg_io_lookup
function). The "lookup" handler has no way of returning a correct
return/error value without knowing whether a file(existing or non-existing)
is for read or write.
I would not like to resort to a workaround of adding a read/write mode
specifier as part of a filename parameter like "/nvram/filename/w" or
"/nvram/filename/r" or "/nvramR"/filename" or "/nvramW/filename". This
would be redundant for fopen().
Is there any other workaround or a solution for this situation? Am I missing
something ?
Here is another wish about I/O device driver handlers. There is no "close"
handler. I could use a "close" handler since it seems to be a right place
to free memory allocated in my "lookup" handler.
-- Masaki S.
next reply other threads:[~1999-11-30 2:59 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
1999-11-30 2:59 Masaki Sawanobori [this message]
1999-11-30 7:36 ` Jonathan Larmour
1999-11-30 14:14 ` Masaki Sawanobori
1999-12-01 3:15 ` Nick Garnett
1999-11-30 7:47 ` Gary Thomas
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