.TH POSTNOTE 2.SH NAMEpostnote \- send a note to a process or process group.SH SYNOPSIS.B #include <u.h>.br.B #include <libc.h>.PP.nf.Bint	postnote(int who, int pid, char *note).fi.SH DESCRIPTION.I Postnotesends a note to a process or process group.If.I whois.BR PNPROC ,then.I noteis written to.BI /proc/ pid /note\f1.If.I whois.BI PNGROUP , the note is delivered to theprocess group by writing.I noteto.BI /proc/ pid /notepg\f1.For.B PNGROUPonly, if the calling process is in the target group, the note is.I notdelivered to that process..PPIf the write is successful, zero is returned.Otherwise \-1 is returned..SH SOURCE.B /sys/src/libc/9sys/postnote.c.SH "SEE ALSO".IR notify (2),.IR intro (2),.IR proc (3).SH DIAGNOSTICSSets.IR errstr .