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      1 /*
      2  * Copyright (C) 2009 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 #ifndef _ANDROID_LOG_H
     18 #define _ANDROID_LOG_H
     19 
     20 /******************************************************************
     21  *
     22  * IMPORTANT NOTICE:
     23  *
     24  *   This file is part of Android's set of stable system headers
     25  *   exposed by the Android NDK (Native Development Kit) since
     26  *   platform release 1.5
     27  *
     28  *   Third-party source AND binary code relies on the definitions
     29  *   here to be FROZEN ON ALL UPCOMING PLATFORM RELEASES.
     30  *
     31  *   - DO NOT MODIFY ENUMS (EXCEPT IF YOU ADD NEW 32-BIT VALUES)
     32  *   - DO NOT MODIFY CONSTANTS OR FUNCTIONAL MACROS
     33  *   - DO NOT CHANGE THE SIGNATURE OF FUNCTIONS IN ANY WAY
     34  *   - DO NOT CHANGE THE LAYOUT OR SIZE OF STRUCTURES
     35  */
     36 
     37 /*
     38  * Support routines to send messages to the Android in-kernel log buffer,
     39  * which can later be accessed through the 'logcat' utility.
     40  *
     41  * Each log message must have
     42  *   - a priority
     43  *   - a log tag
     44  *   - some text
     45  *
     46  * The tag normally corresponds to the component that emits the log message,
     47  * and should be reasonably small.
     48  *
     49  * Log message text may be truncated to less than an implementation-specific
     50  * limit (e.g. 1023 characters max).
     51  *
     52  * Note that a newline character ("\n") will be appended automatically to your
     53  * log message, if not already there. It is not possible to send several messages
     54  * and have them appear on a single line in logcat.
     55  *
     56  * PLEASE USE LOGS WITH MODERATION:
     57  *
     58  *  - Sending log messages eats CPU and slow down your application and the
     59  *    system.
     60  *
     61  *  - The circular log buffer is pretty small (<64KB), sending many messages
     62  *    might push off other important log messages from the rest of the system.
     63  *
     64  *  - In release builds, only send log messages to account for exceptional
     65  *    conditions.
     66  *
     67  * NOTE: These functions MUST be implemented by /system/lib/liblog.so
     68  */
     69 
     70 #include <stdarg.h>
     71 
     72 #ifdef __cplusplus
     73 extern "C" {
     74 #endif
     75 
     76 /*
     77  * Android log priority values, in ascending priority order.
     78  */
     79 typedef enum android_LogPriority {
     80     ANDROID_LOG_UNKNOWN = 0,
     81     ANDROID_LOG_DEFAULT,    /* only for SetMinPriority() */
     82     ANDROID_LOG_VERBOSE,
     83     ANDROID_LOG_DEBUG,
     84     ANDROID_LOG_INFO,
     85     ANDROID_LOG_WARN,
     86     ANDROID_LOG_ERROR,
     87     ANDROID_LOG_FATAL,
     88     ANDROID_LOG_SILENT,     /* only for SetMinPriority(); must be last */
     89 } android_LogPriority;
     90 
     91 /*
     92  * Send a simple string to the log.
     93  */
     94 int __android_log_write(int prio, const char *tag, const char *text);
     95 
     96 /*
     97  * Send a formatted string to the log, used like printf(fmt,...)
     98  */
     99 int __android_log_print(int prio, const char *tag,  const char *fmt, ...)
    100 #if defined(__GNUC__)
    101     __attribute__ ((format(printf, 3, 4)))
    102 #endif
    103     ;
    104 
    105 /*
    106  * A variant of __android_log_print() that takes a va_list to list
    107  * additional parameters.
    108  */
    109 int __android_log_vprint(int prio, const char *tag,
    110                          const char *fmt, va_list ap);
    111 
    112 /*
    113  * Log an assertion failure and SIGTRAP the process to have a chance
    114  * to inspect it, if a debugger is attached. This uses the FATAL priority.
    115  */
    116 void __android_log_assert(const char *cond, const char *tag,
    117 			  const char *fmt, ...)
    118 #if defined(__GNUC__)
    119     __attribute__ ((noreturn))
    120     __attribute__ ((format(printf, 3, 4)))
    121 #endif
    122     ;
    123 
    124 #ifdef __cplusplus
    125 }
    126 #endif
    127 
    128 #endif /* _ANDROID_LOG_H */
    129