# sd_journal_print

## NAME



           sd_journal_print, sd_journal_printv, sd_journal_send,
           sd_journal_sendv, sd_journal_perror, SD_JOURNAL_SUPPRESS_LOCATION,
           sd_journal_print_with_location, sd_journal_printv_with_location,
           sd_journal_send_with_location, sd_journal_sendv_with_location,
           sd_journal_perror_with_location - Submit log entries to the
           journal
    


## SYNOPSIS



           **#include <systemd/sd-journal.h>**
    
           **int sd_journal_print(int** _priority_**, const char ***_format_**, ...);**
    
           **int sd_journal_printv(int** _priority_**, const char ***_format_**,**
                                 **va_list** _ap_**);**
    
           **int sd_journal_send(const char ***_format_**, ...);**
    
           **int sd_journal_sendv(const struct iovec ***_iov_**, int** _n_**);**
    
           **int sd_journal_perror(const char ***_message_**);**
    
           **int sd_journal_print_with_location(int** _priority_**, const char ***_file_**,**
                                              **const char ***_line_**,**
                                              **const char ***_func_**,**
                                              **const char ***_format_**, ...);**
    
           **int sd_journal_printv_with_location(int** _priority_**,**
                                               **const char ***_file_**,**
                                               **const char ***_line_**,**
                                               **const char ***_func_**,**
                                               **const char ***_format_**,**
                                               **va_list** _ap_**);**
    
           **int sd_journal_send_with_location(const char ***_file_**,**
                                             **const char ***_line_**,**
                                             **const char ***_func_**,**
                                             **const char ***_format_**, ...);**
    
           **int sd_journal_sendv_with_location(const char ***_file_**,**
                                              **const char ***_line_**,**
                                              **const char ***_func_**,**
                                              **const struct iovec ***_iov_**,**
                                              **int** _n_**);**
    
           **int sd_journal_perror_with_location(const char ***_file_**,**
                                               **const char ***_line_**,**
                                               **const char ***_func_**,**
                                               **const char ***_message_**);**
    


## DESCRIPTION



           **sd_journal_print()** may be used to submit simple, plain text log
           entries to the system journal. The first argument is a priority
           value. This is followed by a format string and its parameters,
           similar to printf(3) or syslog(3). Note that currently the
           resulting message will be truncated to **LINE_MAX - 8**. 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
           syslog.h, see syslog(3) for details. It is recommended to use this
           call to submit log messages in the application locale or system
           locale and in UTF-8 format, but no such restrictions are enforced.
           Note that log messages written using this function are generally
           not expected to end in a new-line character. However, as all
           trailing whitespace (including spaces, new-lines, tabulators and
           carriage returns) are automatically stripped from the logged
           string, it is acceptable to specify one (or more). Empty lines
           (after trailing whitespace removal) are suppressed. On non-empty
           lines, leading whitespace (as well as inner whitespace) is left
           unmodified.
    
           **sd_journal_printv()** is similar to **sd_journal_print()** but takes a
           variable argument list encapsulated in an object of type _va_list_
           (see stdarg(3) for more information) instead of the format string.
           It 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
           **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. (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-fields(7) for
           details, but additional application defined fields may be used. A
           variable may be assigned more than one value per entry. If this
           function is used, trailing whitespace is automatically removed
           from each formatted field.
    
           **sd_journal_sendv()** is similar to **sd_journal_send()** but takes an
           array of _struct iovec_ (as defined in uio.h, see **readv**(3) 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 particularly useful to submit binary objects
           to the journal where that is necessary. Note that this function
           will not strip trailing whitespace of the passed fields, but
           passes the specified data along unmodified. This is different from
           both **sd_journal_print()** and **sd_journal_send()** described above,
           which are based on format strings, and do strip trailing
           whitespace.
    
           **sd_journal_perror()** is a similar to perror(3) 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 errno(3). 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 wrapper around **sd_journal_sendv()**
           to make it easier to use when only text strings shall be
           submitted. Also, the following two calls are mostly equivalent:
    
               sd_journal_print(LOG_INFO, "Hello World, this is PID %lu!", (unsigned long) getpid());
    
               sd_journal_send("MESSAGE=Hello World, this is PID %lu!", (unsigned long) getpid(),
                               "PRIORITY=%i", LOG_INFO,
                               NULL);
    
           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 **SD_JOURNAL_SUPPRESS_LOCATION** before including
           sd-journal.h.
    
           **sd_journal_print_with_location()** ,
           **sd_journal_printv_with_location()** ,
           **sd_journal_send_with_location()** , **sd_journal_sendv_with_location()** ,
           and **sd_journal_perror_with_location()** are similar to their
           counterparts without "_with_location", but accept additional
           parameters to explicitly set the source file name, function, and
           line. The arguments "file" and "line" must contain valid journal
           entries including the variable name, e.g.  "CODE_FILE=src/foo.c"
           and "CODE_LINE=666", while "func" must only contain the function
           name, i.e. the value without "CODE_FUNC=". These variants are
           primarily useful when writing custom wrappers, for example in
           bindings for a different language.
    
           syslog(3) 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,
           filenames, and functions as metadata along all entries, and
           guaranteeing chronological ordering with structured log entries
           that are generated via **sd_journal_send()**. Using **syslog()** has the
           benefit of being more portable.
    
           These functions implement a client to the **Native Journal**
           **Protocol******[1].


## RETURN VALUE



           The ten functions return 0 on success or a negative errno-style
           error code. The errno(3) variable itself is not altered.
    
           If systemd-journald(8) is not running (the socket is not present),
           those functions do nothing, and also return 0.
    


## THREAD SAFETY



           All functions listed here are thread-safe and may be called in
           parallel from multiple threads.
    
           **sd_journal_sendv()** and **sd_journal_sendv_with_location()** are "async
           signal safe" in the meaning of signal-safety(7).
    
           **sd_journal_print()** , **sd_journal_printv()** , **sd_journal_send()** ,
           **sd_journal_perror()** , and their counterparts with "_with_location"
           are not async signal safe.
    


## NOTES



           Functions described here are available as a shared library, which
           can be compiled against and linked to with the
           **libsystemd pkg-config**(1) file.
    
           The code described here uses getenv(3), which is declared to be
           not multi-thread-safe. This means that the code calling the
           functions described here must not call setenv(3) from a parallel
           thread. It is recommended to only do calls to **setenv()** from an
           early phase of the program when no other threads have been
           started.
    


## NOTES



            1. Native Journal Protocol
               https://systemd.io/JOURNAL_NATIVE_PROTOCOL
    


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