X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=blobdiff_plain;f=man%2Fsd_journal_print.xml;h=638657721f7c0c8a86baccf031bba90921854765;hp=2d5d3639c89a87b00cceb47aa2a900b06785fc90;hb=8dc385e7701726be69b681e2738a1d74a21b24f1;hpb=6aae0ed2d5915c28b27857fe0cf16e01b21a1882 diff --git a/man/sd_journal_print.xml b/man/sd_journal_print.xml index 2d5d3639c..638657721 100644 --- a/man/sd_journal_print.xml +++ b/man/sd_journal_print.xml @@ -47,6 +47,8 @@ sd_journal_printv sd_journal_send sd_journal_sendv + sd_journal_perror + SD_JOURNAL_SUPPRESS_LOCATION Submit log entries to the journal @@ -80,6 +82,11 @@ int n + + int sd_journal_perror + const char* message + + @@ -95,14 +102,14 @@ or syslog3. The priority value is one of - LOG_EMERG, - LOG_ALERT, - LOG_CRIT, - LOG_ERR, - LOG_WARNING, - LOG_NOTICE, - LOG_INFO, - LOG_DEBUG, as defined in + LOG_EMERG, + LOG_ALERT, + LOG_CRIT, + LOG_ERR, + LOG_WARNING, + LOG_NOTICE, + LOG_INFO, + LOG_DEBUG, as defined in syslog.h, see syslog3 for details. It is recommended to use this call to @@ -113,44 +120,61 @@ sd_journal_printv() is similar to sd_journal_print() but takes a variable argument list encapsulated in an - object of type va_list (see + object of type va_list (see stdarg3 for more information) instead of the format string. It - is otherwise equivalent in behaviour. + is otherwise equivalent in behavior. sd_journal_send() may be used to submit structured log entries to the system journal. It takes a series of format strings, each immediately followed by their associated parameters, - terminated by a NULL. The strings passed should be of + terminated by NULL. The strings passed should be of the format VARIABLE=value. The - variable name must be in uppercase and consist only - of characters, numbers and underscores, and may not - begin with an underscore. The value can be of any size - and format. It is highly recommended to submit - text strings formatted in the UTF-8 character encoding - only, and submit binary fields only when formatting in - UTf-8 strings is not sensible. A number of well known - fields are defined, see + variable name must be in uppercase and consist only of + characters, numbers and underscores, and may not begin + with an underscore. (All assignments that do not + follow this syntax will be ignored.) The value can be + of any size and format. It is highly recommended to + submit text strings formatted in the UTF-8 character + encoding only, and submit binary fields only when + formatting in UTF-8 strings is not sensible. A number + of well known fields are defined, see systemd.journal-fields7 for details, but additional application defined fields - may be used. + may be used. A variable may be assigned more than one + value per entry. sd_journal_sendv() is similar to sd_journal_send() but - takes an array of struct iovec (as + takes an array of struct iovec (as defined in uio.h, see readv3 for details) instead of the format string. Each structure should reference one field of the entry to submit. The second argument specifies the number of - structures in the - array. sd_journal_sendv() is + structures in the array. + sd_journal_sendv() is particularly useful to submit binary objects to the journal where that is necessary. + sd_journal_perror() is a + similar to + perror3 + and writes a message to the journal that consists of + the passed string, suffixed with ": " and a human + readable representation of the current error code + stored in + errno3. If + the message string is passed as NULL or empty string, + only the error string representation will be written, + prefixed with nothing. An additional journal field + ERRNO= is included in the entry containing the numeric + error code formatted as decimal string. The log + priority used is LOG_ERR (3). + Note that sd_journal_send() - is a wapper around + is a wrapper around sd_journal_sendv() to make it easier to use when only text strings shall be submitted. Also, the following two calls are @@ -165,21 +189,21 @@ sd_journal_send("MESSAGE=Hello World, this is PID %lu!", (unsigned long) getpid( Note that these calls implicitly add fields for the source file, function name and code line where invoked. This is implemented with macros. If this is - not desired it can be turned off by defining + not desired, it can be turned off by defining SD_JOURNAL_SUPPRESS_LOCATION before including sd-journal.h. syslog3 - and and sd_journal_print() may - mostly be used interchangably + and sd_journal_print() may + largely be used interchangeably functionality-wise. However, note that log messages logged via the former take a different path to the journal server than the later, and hence global chronological ordering between the two streams cannot be guaranteed. Using sd_journal_print() has the - benefit of logging source code line, file names, and - functions as meta data along all entries, and + benefit of logging source code line, filenames, and + functions as metadata along all entries, and guaranteeing chronological ordering with structured log entries that are generated via sd_journal_send(). Using @@ -190,8 +214,23 @@ sd_journal_send("MESSAGE=Hello World, this is PID %lu!", (unsigned long) getpid( Return Value - The four calls return 0 on success or a - negative errno-style error code. + The four calls return 0 on success or a negative + errno-style error code. The + errno3 + variable itself is not altered. + + + + Async signal safety + sd_journal_sendv() is "async signal + safe" in the meaning of signal7. + + + sd_journal_print, + sd_journal_printv, + sd_journal_send, and + sd_journal_perror are + not async signal safe. @@ -201,10 +240,9 @@ sd_journal_send("MESSAGE=Hello World, this is PID %lu!", (unsigned long) getpid( sd_journal_printv(), sd_journal_send() and sd_journal_sendv() interfaces - are available as shared library, which can be compiled + are available as a shared library, which can be compiled and linked to with the - libsystemd-journal - pkg-config1 + libsystemd-journal pkg-config1 file. @@ -213,10 +251,14 @@ sd_journal_send("MESSAGE=Hello World, this is PID %lu!", (unsigned long) getpid( systemd1, - sd-journal7, + sd-journal3, sd_journal_stream_fd3, syslog3, - systemd.journal-fields7 + perror3, + errno3, + systemd.journal-fields7, + signal7, + socket7