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author | Mattias Andrée <maandree@kth.se> | 2017-12-11 23:13:37 +0100 |
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committer | Mattias Andrée <maandree@kth.se> | 2017-12-11 23:13:37 +0100 |
commit | e35ba8684be9951fa2129503477ccd5ed6e4e5fc (patch) | |
tree | 756292d5a18ad6011a9311fdea8159f474385b65 /bus_read.3 | |
parent | typo (diff) | |
download | bus-e35ba8684be9951fa2129503477ccd5ed6e4e5fc.tar.gz bus-e35ba8684be9951fa2129503477ccd5ed6e4e5fc.tar.bz2 bus-e35ba8684be9951fa2129503477ccd5ed6e4e5fc.tar.xz |
Simplify, do not install examples or info manual, and change license3.1.7
Signed-off-by: Mattias Andrée <maandree@kth.se>
Diffstat (limited to 'bus_read.3')
-rw-r--r-- | bus_read.3 | 71 |
1 files changed, 71 insertions, 0 deletions
diff --git a/bus_read.3 b/bus_read.3 new file mode 100644 index 0000000..36fd4c9 --- /dev/null +++ b/bus_read.3 @@ -0,0 +1,71 @@ +.TH BUS_READ 3 BUS +.SH NAME +bus_read, bus_read_timed - Listen for new messages a bus +.SH SYNOPSIS +.LP +.nf +#include <bus.h> +.P +int bus_read(const bus_t *\fIbus\fP, int (*\fIcallback\fP)(const char *\fImessage\fP, void *\fIuser_data\fP), + void *\fIuser_data\fP); +int bus_read_timed(const bus_t *\fIbus\fP, int (*\fIcallback\fP)(const char *\fImessage\fP, void *\fIuser_data\fP), + void *\fIuser_data\fP, const struct timespec *\fItimeout\fP, clockid_t \fIclockid\fP); +.fi +.SH DESCRIPTION +The +.BR bus_read () +function waits for new message to be sent on the bus specified in +\fIbus\fP, as provieded by a previous call to the +.BR bus_open () +function. Once a message is received, the \fIcallback\fP function is +invoked. The \fImessage\fP argument to the callback is the received +message, and \fIuser_data\fP for \fIcallback\fP should be +\fIuser_data\fP from +.BR bus_read (). +However, once +.BR bus_read () +has ensured that it will receive any message sent on the bus, it shall +invoke the \fIcallback\fP function with \fImessage\fP set to \fINULL\fP, +to notify the process that it can perform any action that requires that +it is listening on the bus. +.PP +After \fIcallback\fP returns, \fImessage\fP may be override. Therefore +\fIcallback\fP should copy \fImessage\fP and start a new thread that +uses the copy of \fImessage\fP. \fIcallback\fP shall return -1 on +failure, 0 if +.BR bus_read () +should stop listening or 1 if +.BR bus_read () +should continue listening. +.PP +The +.BR bus_read_timed () +function behaves like +.BR bus_read (), +except it will automatically fail and set \fIerrno\fP to \fBEAGAIN\fP +when the specified time has passed. The time is specified as an +absolute time using the parameter \fItimeout\fP. The behaviour is +unspecified if \fItimeout\fP is \fINULL\fP. \fItimeout\fP is measured +with the clock whose ID is specified by the \fIclockid\fP parameter. +This clock must be a predicitable clock. +.SH RETURN VALUES +Upon successful completion, these functions returns 0. Otherwise the +function returns -1 and sets \fIerrno\fP to indicate the error. +.SH ERRORS +The +.BR bus_read (3) +function may fail and set \fIerrno\fP to any of the errors specified for +.BR semop (3). +The +.BR bus_read_timed (3) +function may also set \fIerrno\fP to any of the errors specified for +.BR clock_gettime (3). +.SH SEE ALSO +.BR bus-create (1), +.BR bus (5), +.BR libbus (7), +.BR bus_open (3), +.BR bus_write (3), +.BR bus_poll (3), +.BR semop (3), +.BR clock_gettime (3) |