syslog() — Send a message to the control log
Standards
Standards / Extensions | C or C++ | Dependencies |
---|---|---|
XPG4.2 |
both |
Format
#define _XOPEN_SOURCE_EXTENDED 1
#include <syslog.h>
void syslog(int priority, const char *message, … /* argument */);
General description
The syslog() function sends a message to an implementation-specific logging facility, which loads it in an appropriate system log, writes it to the system console, forwards it to a list of users, or forwards it to the logging facility on another host over the network. The logged message includes a message header and a message body. The message header consists of a facility indicator, a severity indicator, a timestamp, a tag string, and optionally the process ID. The process ID is surrounded by square brackets. The code point values for the square brackets are taken from code page IBM-1047. The value for the left square bracket is 0xAD. The value for the right square bracket is 0xBD.
The message body is generated from the message and following arguments in the same manner as if these were arguments to the printf() function, except that occurrences of %m in the format string pointed to by the message argument are replaced by the error message string associated with the current value of errno. A trailing newline character is added if needed.
- LOG_ALERT
- A condition that should be corrected immediately, such as a corrupted system database.
- LOG_CRIT
- Critical conditions, such as hard device errors.
- LOG_DEBUG
- Messages that contain information normally of use only when debugging a program.
- LOG_EMERG
- A Panic condition. This is normally broadcast to all processes.
- LOG_ERR
- Errors.
- LOG_INFO
- Informational messages.
- LOG_NOTICE
- Conditions that are not error conditions, but that may require special handling.
- LOG_WARNING
- Warning messages.
- LOG_USER
- Message generated by random processes. This is the default facility identifier if none is specified.
- LOG_LOCAL0
- Reserved for local use.
- LOG_LOCAL1
- Reserved for local use.
- LOG_LOCAL2
- Reserved for local use.
- LOG_LOCAL3
- Reserved for local use.
- LOG_LOCAL4
- Reserved for local use.
- LOG_LOCAL5
- Reserved for local use.
- LOG_LOCAL6
- Reserved for local use.
- LOG_LOCAL7
- Reserved for local use.
Returned value
syslog() returns no values.