sij/mapnik
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

Updated Runtime Logging (markdown)

kunitoki 2012-04-09 14:07:28 -07:00
parent 50a220cab4
commit cb10e0fbdb
1 changed files with 20 additions and 1 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

21
Runtime-Logging.md

@ -19,6 +19,25 @@ Then if we have a file called cairo_renderer.cpp and need to debug a string:
MAPNIK_LOG_DEBUG(cairo_renderer) << "Log my data, visible at DEBUG severity level";
```
## All the logging facilties in C++
```cpp
// Output a string in INFO severity level
MAPNIK_LOG_INFO(object_name) << "This is INFO";
// Output a string in DEBUG severity level
MAPNIK_LOG_DEBUG(object_name) << "This is DEBUG";
// Output a string in WARN severity level
MAPNIK_LOG_WARN(object_name) << "This is WARN";
// Output a string in ERROR severity level
MAPNIK_LOG_ERROR(object_name) << "This is ERROR";
// Output a string in FATAL severity level
MAPNIK_LOG_FATAL(object_name) << "This is FATAL";
```
## Best practices
This has the advantages that it will be optimized automatically by the compiler when ENABLE_LOG is set to False.
But if you need to perform complex code before outputting a string to debug, then it's better to disable those expensive calls completely when log is not enabled:
@ -32,4 +51,4 @@ But if you need to perform complex code before outputting a string to debug, the
const double z = a * connection->get_zoom_from_sql_call();
MAPNIK_LOG_INFO(cairo_renderer) << "Log the variable " << z << ", visible at INFO severity level";
#endif
```
```