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closelog, openlog, setlogmask, syslog, closelog_r, openlog_r, setlogmask_r, syslog_r - Control system log
Standard C Library (libc.so, libc.a)
#include <syslog.h>
void closelog(void);
void openlog(
const char *id,
int log_option,
int facility);
int setlogmask(
int mask_priority);
void syslog(
int priority,
const char *format,...);
The following function declarations do not conform to current standards and are supported only for backward compatibility.
int openlog(
const char *id,
int log_option,
int facility);
int syslog(
int priority,
const char *format,...);
void closelog_r(
struct syslog_data *syslog_data);
int openlog_r(
const char *id,
int log_option,
int facility,
struct syslog_data *syslog_data);
int setlogmask_r(
int mask_priority,
struct syslog_data *syslog_data);
int syslog_r(
int priority,
struct syslog_data *syslog_data,
const char *format,...);
Interfaces documented on this reference page conform to industry standards as follows:
closelog(), openlog(), setlogmask(), syslog(): XPG4-UNIX
Refer to the standards(5) reference page for more information about industry standards and associated tags.
Specifies a string that is attached to the beginning of every message. Specifies logging options. Values of the log_option parameter include: Logs the process ID with each message. This option is useful for identifying daemons. Sends messages to the console if unable to send them to syslogd. This option is useful in daemon processes that have no controlling terminal. Opens the connection to syslogd immediately, instead of when the first message is logged. This option is useful for programs that need to manage the order in which file descriptors are allocated.
The syslog() function writes messages to the system log maintained by the syslogd daemon.
The syslogd daemon reads messages and writes them to the system console or to a log file, or forwards them to the syslogd daemon on the appropriate host.
If the syslog() function cannot pass the message to syslogd, it writes the message on /dev/console, provided the LOG_CONS option is set.
If special processing is required, the openlog() function can be used to initialize the log file.
[Digital] If a program is using the chroot system call, the syslog routine will not work correctly unless the program calls the openlog or openlog_r routine prior to making the call to chroot .
The closelog() function closes the log file.
The setlogmask() function uses the bit mask in the mask_priority parameter to set the new log priority mask and returns the previous mask. Logging is enabled for the levels indicated by the bits in the mask that are set and is disabled where the bits are not set. The default mask allows all priorities to be logged. If the syslog() function is called with a priority mask that does not allow logging of that level of message, then the function returns without logging the message.
The log_option, facility, and priority macros are defined in the <sys/syslog_pri.h> file.
[Digital] The closelog_r(), openlog_r(), syslog_r(), and setlogmask_r() functions are the reentrant versions of the closelog(), openlog(), syslog(), and setlogmask() functions. They are supported in order to maintain backward compatibility with versions of the operating system prior to Tru64 UNIX Version 4.0. They use the syslog_data structure to maintain syslog access state. The data object syslog_data should be initialized to SYSLOG_DATA_INIT.
[XPG4-UNIX] The setlogmask() function returns the previous log priority mask. The closelog(), openlog(), and syslog() functions return no value.
[Digital] The backward-compatible version of the syslog() function returns a value of -1 if either the priority mask excludes this message from being logged, or if an error occurs and it is impossible to send the message to the syslogd daemon or to the system console.
[Digital] Upon successful completion, the backward-compatible version of the openlog() function returns a value of 0 (zero). Otherwise, a value of -1 is returned and errno is set to indicate the error.
Functions: profil(2)
Standards: standards(5) delim off