Please tell me how to get the system time zone dynamically. Can I use dlopen () to get the timezone dynamically, If so, tell me how to do?

Regards,
Lakshmi

Are you trying to set your timezone dynamically, or just retrieve the timezone your computer already has?

technoguy

I am setting the time zone in linux, that change should be reflected in my application's show command. my code segment is like this

gettimezone()
{
int (*tzfile_read)(const char *, unsigned int, const char *);

while(1)
{
handle = dlopen ("libc.a", RTLD_LAZY);
tzfile_read = dlsym (handle, "tzfile_read");
if(error = dlerror())!=NULL)
(
printtf("\r\n error in openning tzfile"));
)
else
{
printf("%s", (*tzfile_read)("/etc/localtime", 0, NULL));
}
dclose(handle);
}
}
I am not getting the timezone dynamically.
Am I using dlopen(), dlsym() correctly

One thing jumps out at me:

I would think the first parameter to 'dlopen' would be:

libc.so

and *not*

libc.a

great!! I could open libc.so using dlopen, I am getting the handle. but the dlsym() function says "undefined symbol __tzfile_read". my code segment is as follows. what could be the problem?

handle = dlopen ("libc.so", RTLD_LAZY);
if (!handle) {
fprintf (stderr, "%s\n", dlerror());
}
tzfile_read = dlsym (handle, "__tzfile_read");
if(error = dlerror())!=NULL)
(
fprintf (stderr, "%s\n", dlerror());
)

Well, I hope you get back to this .....

libc.so is probably *really*:

/lib/libc.so.6

Knowing that, you can use:

nm --dynamic /lib/libc.so.6

to list the symbols exported by that .so (functions that can be called). On my system, I do not see what you are trying to call. Timezone stuff on my system:

gallard@oldpete:~$ nm --dynamic /lib/libc.so.6 | grep tz
0011c338 V tzname
0011c338 D __tzname
0007cfe0 W tzset