标签：pac first var san ons html blank ble style
#include <syslog.h>
void openlog(char*ident,int option ,int facility);
void syslog(int priority,char*format,……)
void closelog()
例子：
openlog(argv[0], LOG_PID, LOG_LOCAL5);
a. openlog会指定一个indent，那么这个程序的每个信息前面都有这个indent，一般是这个程序名。
b. option控制syslog行为：
option
The option argument to openlog() is an OR of any of these:
LOG_CONS Write directly to system console if there is an error while sending to system logger.
LOG_NDELAY Open the connection immediately (normally, the connection is opened when the first message is logged).
LOG_NOWAIT Don‘t wait for child processes that may have been created while logging the message. (The GNU C library does not create a child
process, so this option has no effect on Linux.)
LOG_ODELAY The converse of LOG_NDELAY; opening of the connection is delayed until syslog() is called. (This is the default, and need not be
specified.)
LOG_PERROR (Not in POSIX.1-2001 or POSIX.1-2008.) Print to stderr as well.
LOG_PID Include PID with each message.
c. The facility argument is used to specify what type of program is logging the message. This lets the configuration file specify that messages from
different facilities will be handled differently.
配置文件是/etc/syslog.conf，可以配置不同程序类型，保存不同的位置：
kern.* /var/log/kern.log
user.* /var/log/syslog
local2.* /var/log/network.log
local3.* /var/log/onvif.log
local5.* /var/log/media.log
local6.* /var/log/rtspd.log
例子：
syslog(LOG_DEBUG, "This is test message %s\n", argv[0]);
第一个参数是level，表示消息的重要性，syslog man page里关于level的选项，从上往下重要性逐渐下降。
level
This determines the importance of the message. The levels are, in order of decreasing importance:
LOG_EMERG system is unusable
LOG_ALERT action must be taken immediately
LOG_CRIT critical conditions
LOG_ERR error conditions
LOG_WARNING warning conditions
LOG_NOTICE normal, but significant, condition
LOG_INFO informational message
LOG_DEBUG debug-level message
后面的参数就是fmt与参数。
closelog()关闭描述符。是否使用是可选的。
标签：pac first var san ons html blank ble style
原文地址：https://www.cnblogs.com/gr-nick/p/11125762.html
