liblog: Add README
Change-Id: I9d789e08e9301ec8afa7be8bede955379694b904
diff --git a/liblog/README b/liblog/README
new file mode 100644
index 0000000..d7472e4
--- /dev/null
+++ b/liblog/README
@@ -0,0 +1,134 @@
+LIBLOG(3) Android NDK Programming Manual LIBLOG(3)
+
+
+
+NAME
+ liblog - Android NDK logger interfaces
+
+SYNOPSIS
+ #include <log/log.h>
+
+ ALOG(android_priority, tag, format, ...)
+ IF_ALOG(android_priority, tag)
+ LOG_PRI(priority, tag, format, ...)
+ LOG_PRI_VA(priority, tag, format, args)
+ #define LOG_TAG NULL
+ ALOGV(format, ...)
+ SLOGV(format, ...)
+ RLOGV(format, ...)
+ ALOGV_IF(cond, format, ...)
+ SLOGV_IF(cond, format, ...)
+ RLOGV_IF(cond, format, ...)
+ IF_ALOGC()
+ ALOGD(format, ...)
+ SLOGD(format, ...)
+ RLOGD(format, ...)
+ ALOGD_IF(cond, format, ...)
+ SLOGD_IF(cond, format, ...)
+ RLOGD_IF(cond, format, ...)
+ IF_ALOGD()
+ ALOGI(format, ...)
+ SLOGI(format, ...)
+ RLOGI(format, ...)
+ ALOGI_IF(cond, format, ...)
+ SLOGI_IF(cond, format, ...)
+ RLOGI_IF(cond, format, ...)
+ IF_ALOGI()
+ ALOGW(format, ...)
+ SLOGW(format, ...)
+ RLOGW(format, ...)
+ ALOGW_IF(cond, format, ...)
+ SLOGW_IF(cond, format, ...)
+ RLOGW_IF(cond, format, ...)
+ IF_ALOGW()
+ ALOGE(format, ...)
+ SLOGE(format, ...)
+ RLOGE(format, ...)
+ ALOGE_IF(cond, format, ...)
+ SLOGE_IF(cond, format, ...)
+ RLOGE_IF(cond, format, ...)
+ IF_ALOGE()
+ LOG_FATAL(format, ...)
+ LOG_ALWAYS_FATAL(format, ...)
+ LOG_FATAL_IF(cond, format, ...)
+ LOG_ALWAYS_FATAL_IF(cond, format, ...)
+ ALOG_ASSERT(cond, format, ...)
+ LOG_EVENT_INT(tag, value)
+ LOG_EVENT_LONG(tag, value)
+
+ Link with -llog
+
+ #include <log/logger.h>
+
+ log_id_t android_logger_get_id(struct logger *logger)
+ int android_logger_clear(struct logger *logger)
+ int android_logger_get_log_size(struct logger *logger)
+ int android_logger_get_log_readable_size(struct logger *logger)
+ int android_logger_get_log_version(struct logger *logger)
+
+ struct logger_list *android_logger_list_alloc(int mode, unsigned int
+ tail, pid_t pid)
+ struct logger *android_logger_open(struct logger_list *logger_list,
+ log_id_t id)
+ struct logger_list *android_logger_list_open(log_id_t id, int mode,
+ unsigned int tail, pid_t pid)
+
+ int android_logger_list_read(struct logger_list *logger_list, struct
+ log_msg *log_msg
+
+ void android_logger_list_free(struct logger_list *logger_list)
+
+ log_id_t android_name_to_log_id(const char *logName)
+ const char *android_log_id_to_name(log_id_t log_id)
+
+ Link with -llog
+
+DESCRIPTION
+ liblog represents an interface to the volatile Android Logging system
+ for NDK (Native) applications and libraries. Interfaces for either
+ writing or reading logs. The log buffers are divided up in Main, Sys‐
+ tem, Radio and Events sub-logs.
+
+ The logging interfaces are a series of macros, all of which can be
+ overridden individually in order to control the verbosity of the appli‐
+ cation or library. [ASR]LOG[VDIWE] calls are used to log to BAsic,
+ System or Radio sub-logs in either the Verbose, Debug, Info, Warning or
+ Error priorities. [ASR]LOG[VDIWE]_IF calls are used to perform thus
+ based on a condition being true. IF_ALOG[VDIWE] calls are true if the
+ current LOG_TAG is enabled at the specified priority. LOG_ALWAYS_FATAL
+ is used to ALOG a message, then kill the process. LOG_FATAL call is a
+ variant of LOG_ALWAYS_FATAL, only enabled in engineering, and not
+ release builds. ALOG_ASSERT is used to ALOG a message if the condition
+ is false; the condition is part of the logged message.
+ LOG_EVENT_(INT|LONG) is used to drop binary content into the Events
+ sub-log.
+
+ The log reading interfaces permit opening the logs either singly or
+ multiply, retrieving a log entry at a time in time sorted order,
+ optionally limited to a specific pid and tail of the log(s) and finally
+ a call closing the logs. A single log can be opened with android_log‐
+ ger_list_open; or multiple logs can be opened with android_log‐
+ ger_list_alloc, calling in turn the android_logger_open for each log
+ id. Each entry can be retrieved with android_logger_list_read. The
+ log(s) can be closed with android_logger_list_free. The logs should be
+ opened with an O_RDONLY mode. O_NDELAY mode will report when the log
+ reading is done with an EAGAIN error return code, otherwise the
+ android_logger_list_read call will block for new entries.
+
+ The value returned by android_logger_open can be used as a parameter to
+ the android_logger_clear function to empty the sub-log. It is recom‐
+ mended to only open log O_WRONLY.
+
+ The value returned by android_logger_open can be used as a parameter to
+ the android_logger_get_log_(size|readable_size|version) to retrieve the
+ sub-log maximum size, readable size and log buffer format protocol ver‐
+ sion respectively. android_logger_get_id returns the id that was used
+ when opening the sub-log. It is recommended to open the log O_RDONLY
+ in these cases.
+
+SEE ALSO
+ syslogd(8)
+
+
+
+ 17 Dec 2013 LIBLOG(3)