logger_default_log() specifications

Signature

static logger_status_t logger_default_log(void *backend, const char *message);

Purpose

Write one log record through the logger_default backend.

Preconditions

• backend must designate a valid logger_default_t backend object.
• The designated backend must have been initialized with:
  • a valid target stream,
  • a valid time_ops table.
• These preconditions are enforced as internal invariants, not as recoverable public argument validation.

Invalid arguments

• message == NULL
  • returns LOGGER_STATUS_INVALID.

Success

• Returns LOGGER_STATUS_OK.
• Writes a UTC+0 timestamp prefix to the configured target stream.
• The formatted timestamp prefix has the form: [YYYY-MM-DD HH:MM:SS UTC+0]
• For example, epoch time 0 is formatted as: [1970-01-01 00:00:00 UTC+0]
• Writes the full contents of message immediately after that trailing space.
• If append_newline == true, writes one trailing newline character after the message.
• If the injected time service cannot provide the current time, a fallback timestamp-error prefix is written instead of a formatted UTC+0 timestamp.
• The fallback prefix is: [timestamp error]
• This fallback prefix also ends with a trailing space character before the message payload.

Failure

• Returns LOGGER_STATUS_IO_ERROR if:
  • writing the timestamp prefix fails,
  • writing the fallback timestamp-error prefix fails,
  • writing message fails,
  • writing the optional trailing newline fails,
  • or any of these writes is partial.
• Returns any non-LOGGER_STATUS_OK status propagated by the private timestamp writing helper, if that helper fails before message emission can complete.

Ownership

• Does not take ownership of backend.
• Does not modify or retain ownership of message.

Notes

• message is treated as a NUL-terminated string.
• strlen(message) determines the number of bytes written for the message payload.
• The function validates message explicitly, but treats backend and backend internals as construction-time invariants.