[En-Nut-Discussion] is there a better set of definitons for fcntl.h ???

[Douglas Pearless]

Hi,

When working on updating the fat.c driver for the MMC cards, I noticed that
_O_RDONLY in fcntl.h was set to 0x0000.

I noticed that there was no 0x0004 in the sequence either, can I suggest
rather than:

#define _O_RDONLY	0x0000	/*!< Read only. */
#define _O_WRONLY	0x0001	/*!< Write only. */
#define _O_RDWR	0x0002	/*!< Read and write. */
#define _O_APPEND 0x0008  	/*!< Start writing at the end. */
#define _O_CREAT	0x0100	/*!< Create file if it does not exist. */
#define _O_TRUNC	0x0200	/*!< Truncate file if it exists. */
#define _O_EXCL	0x0400	/*!< Open only if it does not exist. */
#define _O_TEXT	0x4000	/*!< EOL translation. */
#define _O_BINARY	0x8000	/*!< Raw mode. */ 

Would it not be better to have:

#define _O_RDONLY	0x0004	/*!< Read only. */
#define _O_WRONLY	0x0001	/*!< Write only. */
#define _O_RDWR	0x0002	/*!< Read and write. */
#define _O_APPEND 0x0008  	/*!< Start writing at the end. */
#define _O_CREAT	0x0100	/*!< Create file if it does not exist. */
#define _O_TRUNC	0x0200	/*!< Truncate file if it exists. */
#define _O_EXCL	0x0400	/*!< Open only if it does not exist. */
#define _O_TEXT	0x4000	/*!< EOL translation. */
#define _O_BINARY	0x8000	/*!< Raw mode. */

Which would simplify the checking of _O_RDONLY in code, and make it more
readable?

I noticed that in UART.c and USART.c they use a test like:

"if ((mode & 0x0003) != _O_RDONLY) {" 
And
"if ((mode & 0x0003) != _O_WRONLY) {"

Which means that you have to know the value of _O_RDONLY and _O_WRONLY in
order to understand the code (from a novices point of view).  Also if the
values of _O_aaaaa ever change, then the code in UART.c and USART.c will
break!

That code could to change to (check my code unless I made an error):
"if (!(mode & _O_RDONLY)) {"
and
"if (!(mode & _O_WRONLY)) {"

Which IMHO is more readable and 'safer' as 
Is this a better idea?

These appear to be the only places affected in NutOS

Douglas

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