User  |  Syst  |  Libr  |  Device  |  Files  |  Other  |  Admin  |  Head  |

---

   sd_journal_stream_fd    ( 3 )

---

---

Имя (Name)

sd_journal_stream_fd - Create log stream file descriptor to the
       journal

---

Синопсис (Synopsis)

#include <systemd/sd-journal.h>

       int sd_journal_stream_fd(const char *identifier, int priority,
                                int level_prefix);

---

Описание (Description)

sd_journal_stream_fd() may be used to create a log stream file
       descriptor. Log messages written to this file descriptor as
       simple newline-separated text strings are written to the journal.
       This file descriptor can be used internally by applications or be
       made standard output or standard error of other processes
       executed.

       sd_journal_stream_fd() takes a short program identifier string as
       first argument, which will be written to the journal as
       SYSLOG_IDENTIFIER= field for each log entry (see
       systemd.journal-fields(7) for more information). The second
       argument shall be the default priority level for all messages.
       The priority level 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. The third argument is a
       boolean: if true kernel-style log level prefixes (such as
       SD_WARNING) are interpreted, see sd-daemon(3) for more
       information.

       It is recommended that applications log UTF-8 messages only with
       this API, but this is not enforced.

       Each invocation of sd_journal_stream_fd() allocates a new log
       stream file descriptor, that is not shared with prior or later
       invocations. The file descriptor is write-only (its reading
       direction is shut down), and O_NONBLOCK is turned off initially.

---

Возвращаемое значение (Return value)

The call returns a valid write-only file descriptor on success or
       a negative errno-style error code.

---

Безопасность сигналов (Signal safety)

sd_journal_stream_fd() is "async signal safe" in the meaning of
       signal-safety(7).

---

Примечание (Note)

All functions listed here are thread-safe and may be called in
       parallel from multiple threads.

       These APIs are implemented as a shared library, which can be
       compiled and linked to with the libsystemd pkg-config(1) file.

---

Примеры (Examples)

Creating a log stream suitable for fprintf(3):

           #include <syslog.h>
           #include <stdio.h>
           #include <string.h>
           #include <unistd.h>
           #include <systemd/sd-journal.h>
           #include <systemd/sd-daemon.h>

           int main(int argc, char *argv[]) {
             int fd;
             FILE *log;
             fd = sd_journal_stream_fd("test", LOG_INFO, 1);
             if (fd < 0) {
               fprintf(stderr, "Failed to create stream fd: %s\n", strerror(-fd));
               return 1;
             }
             log = fdopen(fd, "w");
             if (!log) {
               fprintf(stderr, "Failed to create file object: %m\n");
               close(fd);
               return 1;
             }
             fprintf(log, "Hello World!\n");
             fprintf(log, SD_WARNING "This is a warning!\n");
             fclose(log);
             return 0;
           }

---

Смотри также (See also)

systemd(1), sd-journal(3), sd-daemon(3), sd_journal_print(3),
       syslog(3), fprintf(3), systemd.journal-fields(7)

---