postnote - send a note to a process or process group #include <u.h>

#include <libc.h>

 int postnote(int who, int pid, char *note)

Postnote sends a note to a process or process group. If who is PNPROC , then note is written to /proc/ pid /note\f1. If who is PNGROUP , the note is delivered to the process group by writing note to /proc/ pid /notepg\f1. For PNGROUP only, if the calling process is in the target group, the note is not delivered to that process.

If the write is successful, zero is returned. Otherwise -1 is returned.

/sys/src/libc/9sys/postnote.c notify (2), intro (2), proc (3) Sets errstr .