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Old 03-18-2007, 04:21 AM   #1
g4j31a5
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Code for changing system's local date & time


Hi, I planned to make a program to change the local date and time of my machine permanently (just like in yast). So if I rebooted it after changing the date & time with that application, it will be the current date & time of the machine. But the truth is I don't know how. Can anybody help me? Thanks a lot.
 
Old 03-18-2007, 04:58 AM   #2
gnashley
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Why not use hwclock?
 
Old 03-18-2007, 07:56 AM   #3
g4j31a5
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Quote:
Originally Posted by gnashley
Why not use hwclock?
I've looked at the man page of hwclock. So basically I've just to call
Code:
system ("hwclock --set --date="blabla..."");
Right?
 
Old 03-18-2007, 12:52 PM   #4
gnashley
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UTC=`grep UTC /etc/adjtime`
if [ "$UTC" == "UTC" ] ; then
UTC="--utc"
fi

To set the hardware clock:
/sbin/hwclock --set $UTC --date "$NEWDATE $NEWTIME"
To set the system time:
/sbin/hwclock --hctosys $UTC
 
Old 03-18-2007, 02:03 PM   #5
g4j31a5
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Thanks. FYI, I'm trying make a simple GUI for changing the time with SDL & SDL ttf. One more thing though, it seems like hwclock can only be called from root. But I needed everyone to be able to change the date and time with my application. How do I do that?
 
Old 03-18-2007, 03:45 PM   #6
indienick
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If you're trying to allow any low-end user to change the time using an executable runnable to only root, you have several options:
Option 1: In the installation/setup procedures, "chmod" the hwclock executable so it can be executed by all (eg. "chmod a+x /path/to/hwclock").
Option 2: Utilize "sudo".
Option 3: Force the user to provide the root password if they wish to apply any changes they've made.

There's more than likely a reason why the executable has default permissions of being root-only, and it's more than likely best not to tamper with it; if you need to be root to run it, there's a reason for it. This is UNIX/Linux, not Windows.
 
Old 03-20-2007, 09:30 PM   #7
g4j31a5
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Quote:
Originally Posted by indienick
If you're trying to allow any low-end user to change the time using an executable runnable to only root, you have several options:
Option 1: In the installation/setup procedures, "chmod" the hwclock executable so it can be executed by all (eg. "chmod a+x /path/to/hwclock").
Option 2: Utilize "sudo".
Option 3: Force the user to provide the root password if they wish to apply any changes they've made.

There's more than likely a reason why the executable has default permissions of being root-only, and it's more than likely best not to tamper with it; if you need to be root to run it, there's a reason for it. This is UNIX/Linux, not Windows.
Thanks. Will do that. Yeah, I know it's Linux, but I needed it to behave more like a Windows nevertheless. The requirement needed so.
 
Old 03-21-2007, 04:59 AM   #8
gnashley
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The code I posted is just a part of an example program included with Xdialog, which uses the gtk libs. Why not just use that instead of sdl?
 
Old 03-21-2007, 06:02 AM   #9
g4j31a5
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Quote:
Originally Posted by gnashley
The code I posted is just a part of an example program included with Xdialog, which uses the gtk libs. Why not just use that instead of sdl?
Well I needed sdl because that's the requirement. So whether I like it or not, I must use a system call to hwclock with C++.
 
  


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