83 lines
2.7 KiB
Markdown
83 lines
2.7 KiB
Markdown
![]() |
# log.c
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A simple logging library implemented in C99
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![screenshot](https://cloud.githubusercontent.com/assets/3920290/23831970/a2415e96-0723-11e7-9886-f8f5d2de60fe.png)
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## Usage
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**[log.c](src/log.c?raw=1)** and **[log.h](src/log.h?raw=1)** should be dropped
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into an existing project and compiled along with it. The library provides 6
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function-like macros for logging:
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```c
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log_trace(const char *fmt, ...);
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log_debug(const char *fmt, ...);
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log_info(const char *fmt, ...);
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log_warn(const char *fmt, ...);
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log_error(const char *fmt, ...);
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log_fatal(const char *fmt, ...);
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```
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Each function takes a printf format string followed by additional arguments:
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```c
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log_trace("Hello %s", "world")
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```
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Resulting in a line with the given format printed to stderr:
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```
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20:18:26 TRACE src/main.c:11: Hello world
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```
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#### log_set_quiet(bool enable)
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Quiet-mode can be enabled by passing `true` to the `log_set_quiet()` function.
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While this mode is enabled the library will not output anything to `stderr`, but
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will continue to write to files and callbacks if any are set.
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#### log_set_level(int level)
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The current logging level can be set by using the `log_set_level()` function.
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All logs below the given level will not be written to `stderr`. By default the
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level is `LOG_TRACE`, such that nothing is ignored.
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#### log_add_fp(FILE *fp, int level)
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One or more file pointers where the log will be written can be provided to the
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library by using the `log_add_fp()` function. The data written to the file
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output is of the following format:
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```
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2047-03-11 20:18:26 TRACE src/main.c:11: Hello world
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```
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Any messages below the given `level` are ignored. If the library failed to add a
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file pointer a value less-than-zero is returned.
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#### log_add_callback(log_LogFn fn, void *udata, int level)
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One or more callback functions which are called with the log data can be
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provided to the library by using the `log_add_callback()` function. A callback
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function is passed a `log_Event` structure containing the `line` number,
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`filename`, `fmt` string, `va` printf va\_list, `level` and the given `udata`.
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#### log_set_lock(log_LockFn fn, void *udata)
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If the log will be written to from multiple threads a lock function can be set.
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The function is passed the boolean `true` if the lock should be acquired or
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`false` if the lock should be released and the given `udata` value.
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#### const char* log_level_string(int level)
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Returns the name of the given log level as a string.
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#### LOG_USE_COLOR
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If the library is compiled with `-DLOG_USE_COLOR` ANSI color escape codes will
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be used when printing.
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## License
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This library is free software; you can redistribute it and/or modify it under
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the terms of the MIT license. See [LICENSE](LICENSE) for details.
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