ref: ec35f468e0eba87c9f09cbbe5fa8af2591e6f914
dir: /man/4/logfile/
.TH LOGFILE 4 .SH NAME logfile \- memory-based append-only circular storage buffer .SH SYNOPSIS .B logfile .RB [ \-\fIsize\fP ] .I \fIfile\fP .SH DESCRIPTION .I Logfile creates a name at .I file (the containing directory must already exist). Each write to .I file appends the written data up to a maximum of .I size bytes; subsequent writes erase the existing data in a circular fashion. A read from .I file will return any currently stored data, if any; if there is none, then it will block until more data becomes available. Multiple readers will receive the data independently of one another. If a writing process is consistently producing data faster than a reading process, then the data read will have some bytes elided; a write is never blocked. .SH SOURCE .B /appl/cmd/logfile.b .SH SEE ALSO .IR wm-logwindow (1), .IR sys-file2chan (2) .SH BUGS Restrictions on .IR sys-file2chan (2) mean that the .I logfile process will not terminate automatically when its file is removed or unmounted. .PP There is no indication to a reader of any missing data. .PP It is not possible to do a non-blocking read of the log file.