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Old 09-01-2003, 05:49 AM   #1
alchen1999
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Get Log file content by C/C++ program


hi, anyone know how to get log file contents (/var/log) by C/C++
program. need your help. thanks
 
Old 09-01-2003, 08:53 AM   #2
loic1
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If what you want to do is similar to the Log Viewer of Red Hat., I'd recommend that you fopen(3) the log file (/var/log/syslog for instance), fseek(3) 10 kilo bytes from the end of the file, loop with fgets(3) until the end of the file (discard the first line which is likely to be partially filled), ftell(3) to know the byte ofset of the end of the file and memorize it, fclose(3). After sleeping for a second or two, fopen(3) again and do the same, starting from the memorized offset given by ftell(3).

There are some tricky issues to address all the problems (log rotating etc.). It might be a lot easier to cut/paste code from GNU tail(1), provided you intend to release your software under a license that is compatible with the GNU GPL.
 
Old 09-01-2003, 09:15 AM   #3
bigFro
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Re: Get Log file content by C/C++ program

Quote:
Originally posted by alchen1999
hi, anyone know how to get log file contents (/var/log) by C/C++
program. need your help. thanks
If you just need to read them, just use your standard open functions . If you need to write them, read up on syslog(3c).

-bF
 
Old 09-03-2003, 05:01 AM   #4
alchen1999
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hi, thanks you's description. But i'd like to get the information by API. did linux support the API to get the log information? need help. Thanks again
 
Old 09-04-2003, 10:55 AM   #5
loic1
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You mention an "API to get information about log files" but I'm not aware of any API that would provide this specific service. It would probably be nice to have a library with a clear API addressing this specific problem. Maybe you could get the code from tail and package it into a small and documented library ? That would definitely be useful. Such a library would need to address all the gory details and that's a lot of tedious work. That's probably the reason why it does not exist yet.
 
  


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