From 41c3d98e8951107970a35f6104e1cbf15cd87ada Mon Sep 17 00:00:00 2001 From: Jonathan McCrohan Date: Wed, 4 Apr 2012 00:11:39 +0100 Subject: modbuslog: flush serial IO buffers on modbus error --- src/modbuslog.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) diff --git a/src/modbuslog.c b/src/modbuslog.c index cb509ea..3f9b658 100644 --- a/src/modbuslog.c +++ b/src/modbuslog.c @@ -44,6 +44,9 @@ #include +#include +#include + // handle SIGALRM by resetting it void minute_check(int signum) { alarm(60); @@ -271,6 +274,21 @@ int main(int argc, char *argv[]) { // back off for 2 secs, increasing by 2 for each // incorrect reply sleep(2+retry*2); + + // open serial port file descriptor, + // flush IO, write zero-ouput, reflush IO, + // close file descriptor + int fd = open(modbus_device_address, O_RDWR | O_NOCTTY ); + if (tcflush(fd, TCIOFLUSH) == 0){ + syslog(LOG_WARNING, "Flushing [%s] serial IO buffer", modbus_device_address); + } + if (tcsendbreak(fd, 0) == 0){ + syslog(LOG_WARNING, "Writing zero-value bits to [%s]", modbus_device_address); + } + if (tcflush(fd, TCIOFLUSH) == 0){ + syslog(LOG_WARNING, "Reflushing [%s] serial IO buffer", modbus_device_address); + } + close(fd); } retry++; } while ((rc == -1) && (retry <= modbus_retry)); -- cgit v1.2.3