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Old 04-27-2012, 11:01 PM   #1
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System Call Return Values Question

Hi all,
This is my first post but I have been coming to the site for a long time now.

I have a question regarding creating my own system calls in Ubuntu(version 2.6.35).
I have created my system calls and they work perfectly with the exception that when I check the return value for known bad input in my driver file (how I am calling and testing my system calls) I always receive a negative one. I know my system calls are working because when I use the dmesg command I can see what the system calls are returning right before they return.
When I give valid input my return values match with those in my driver file, what I expect, and the values returned from dmesg. Does anyone have any idea what the reason for this is?


sample output:

Output from dmesg:
[ 2030.296446] rmMbox421:
[ 2030.296447] Mailbox ID: 9
[ 2030.296457] Mailbox 9 could not be removed (DNE).
[ 2030.296461] **Remove Mailbox returned -3

Output from proj2Driver.c:
0) Hello World
1) Create Mailbox
2) Remove Mailbox
3) Count Mailbox
4) List Mailbox
5) Send Message
10) Quit

Enter Option: 2

Enter Mailbox ID: 9
Result from rmMbox421: -1
Old 04-27-2012, 11:11 PM   #2
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Old 04-28-2012, 08:32 AM   #3
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