.\" (C) 2023, NGINX, Inc.
.\"
.TH nxt_unit_log 3 (date) "NGINX Unit (unreleased)"
.SH Name
nxt_unit_log, nxt_unit_alert, nxt_unit_error, nxt_unit_warn, nxt_unit_debug
\- print messages to the debug log
.SH Library
NGINX Unit library
.RI ( libunit ", " -lunit )
.SH Synopsis
.nf
.B #include <nxt_unit.h>
.PP
.B enum {
.B "    NXT_UNIT_LOG_ALERT,"
.B "    NXT_UNIT_LOG_ERR,"
.B "    NXT_UNIT_LOG_WARN,"
.B "    NXT_UNIT_LOG_NOTICE,"
.B "    NXT_UNIT_LOG_INFO,"
.B "    NXT_UNIT_LOG_DEBUG,"
.B };
.PP
.B [[gnu::format(printf, 3, 4)]]
.BI "void nxt_unit_log(nxt_unit_ctx_t *_Nullable " ctx ", int " level ,
.BI "                  const char *" fmt ", ...);"
.PP
.BI "#define nxt_unit_alert(" ctx ", " fmt ", ...)  \fR/* ... */\fP"
.BI "#define nxt_unit_error(" ctx ", " fmt ", ...)  \fR/* ... */\fP"
.BI "#define nxt_unit_warn(" ctx ", " fmt ", ...)   \fR/* ... */\fP"
.BI "#define nxt_unit_debug(" ctx ", " fmt ", ...)  \fR/* ... */\fP"
.fi
.SH Arguments
.TP
.I ctx
Thread or main context object.
See
.MR nxt_unit_init 3
and
.MR nxt_unit_ctx_alloc 3 .
If NULL is passed,
the output will be printed to standard error.
.TP
.I level
Log level (see the
.IR enum ).
.TP
.I fmt
See
.MR snprintf 3 .
.SH Description
.MR nxt_unit_log 3
writes a formatted string into the Unit debug log,
prefixed with information about the application,
and appended by a new-line character.
.PP
The macros are just wrappers around
.MR nxt_unit_log 3
that pass a specific log level.
.SH Return value
None.
.SH Errors
If these functions fail to write to the Unit debug log,
they will fall back to standard error.
.SH Files
.TP
.I /usr/local/var/log/unit/unit.log
Unit debug log.
See
.MR unitd 8 .
.SH Examples
See
.MR nxt_unit_init 3 .
.SH Copyright
(C) 2017-2023, NGINX, Inc.
.PP
SPDX-License-Identifier: Apache-2.0
.SH See also
.MR nxt_unit_req_log 3 ,
.MR unitd 8 .
.PP
.UR https://unit.nginx.org
Website
.UE
.PP
.UR https://mailman.nginx.org/mailman/listinfo/unit
Mailing list
.UE
.PP
.UR https://github.com/nginx/unit
GitHub
.UE