repos_ecs/其他2015后/日志库/log4c-1.2.4/examples

Sample programs using Log4C
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Please refer to the developers guide in the doc directory for a fuller
explanation of these examples.

helloworld -- classic simple program that logs the message "Hello World!" using Log4C.
This example is used in the developers guide to explain some fundamental Log4C
concepts.

helloworld1 -- again the classic hello world example but demonstrating a technique
for wrapping Log4C API calls to make it easy to remove Log4C from your code and
demonstrating how to use a macro so that you name the category for your file just
once at the start of the file.

application_1 -- most basic example of using log4c. Notice that you
only have to setup the category. Log4c is more powerful and flexible
if you use the log4crc file to setup the relationship between
category, appender, and formatter.

application_2 -- example of using log4c with custom written appenders
and formatters. Notice in Makefile.am that the linking for
application_2 includes an additional library. This is an example of
how you as a user of log4c would add in appenders and formatters.

application_3 -- example of using log4c with extended user information.
You would use this if your logging wanted to add things like which
process_id, which machine, or any other additional location information
you wanted to add to your logging. Notice that you have to write
your own formatter that knows to look for the additional information.

log4crc -- Notice the specifiers of how the catgories from the two
example applications are wired up to appenders and formatters. Notice
how when specifying a layout and appender, the type= string must match
the name of the appender/formatter given in the code, but that the
name= can be any name you want. Try and alter the priority= settings,
the appender and layout settings in log4crc and rerunning the examples
to see how the config affects which error messages will be printed.
A new category to log to a rollingfile appender has been added

reread -- If you used the --enable-reread flag during ./configure, you
can test log4crc reread by running application_2 for 30 seconds, and
while it is running edit the log4crc file and change the output level
for application 2 between debug and error using a second window. In
the window running application_2 you should notice the logging
behaviour changes accordingly