Updated: April 19, 2023 |
Send a message to the system logger
#include <stdio.h> #include <sys/slog.h> int slogf( int opcode, int severity, const char * fmt, ... );
Use major codes in the range _SLOGC_PRIVATE_START and _SLOGC_PRIVATE_END in your applications, keeping in mind that many applications already use _SLOGC_TEST, which is (_SLOGC_PRIVATE_START + 0).
The formatting characters that you use in the message determine any additional arguments.
libc
Use the -l c option to qcc to link against this library. This library is usually included automatically.
The slog*() functions send log messages to the system logger, slogger2. To send formatted messages, use slogf(). If you have programs that scan log files for specified codes, you can use slogb() or slogi() to send a block of structures or ints, respectively.
The vslogf() function is an alternate form in which the arguments have already been captured using the variable-length argument facilities of <stdarg.h>.
Severity levels
There are eight levels of severity defined. The lowest severity is 7 and the highest is 0. The default is 7.
Manifest Name | Severity value | Description |
---|---|---|
_SLOG_SHUTDOWN | 0 | Shut down the system NOW (e.g., for OEM use) |
_SLOG_CRITICAL | 1 | Unexpected unrecoverable error (e.g., hard disk error) |
_SLOG_ERROR | 2 | Unexpected recoverable error (e.g., needed to reset a hardware controller) |
_SLOG_WARNING | 3 | Expected error (e.g., parity error on a serial port) |
_SLOG_NOTICE | 4 | Warnings (e.g., out of paper) |
_SLOG_INFO | 5 | Information (e.g., printing page 3) |
_SLOG_DEBUG1 | 6 | Debug messages (normal detail) |
_SLOG_DEBUG2 | 7 | Debug messages (fine detail) |
If you want the data in the log message to be interpreted as text, use a bitwise OR to add _SLOG_TEXTBIT to the severity. If this bit is set, slogf() and vslogf() also write the log message on stderr.
The size of the message sent to slogger2, or -1 if an error occurs.
Any value from the Errors section in MsgSend(), as well as:
#include <stdio.h> #include <unistd.h> #include <stdlib.h> #include <sys/slog.h> #include <sys/slogcodes.h> int main() { int i; for(i = 0 ; ; i++) { switch(rand() % 3) { case 0: slogb( _SLOG_SETCODE(_SLOGC_TEST, 0), _SLOG_DEBUG1, &i, sizeof(i)); break; case 1: slogi( _SLOG_SETCODE(_SLOGC_TEST, 1), _SLOG_CRITICAL, 1, i); break; case 2: slogf( _SLOG_SETCODE(_SLOGC_TEST, 2), _SLOG_ERROR, "This is number %d", i); break; } sleep(1); } }
Safety: | |
---|---|
Cancellation point | Yes |
Interrupt handler | No |
Signal handler | Yes |
Thread | Yes |