AIX socket don't have MSG_DONTWAIT tag

[poulacou]

MSG_DONTWAIT could be replaced by MSG_NONBLOCK on AIX

** on Linux we have:

grep MSG_DONTWAIT /usr/include/bits/socket.h

MSG_DONTWAIT    = 0x40, /* Nonblocking IO.  */

define MSG_DONTWAIT MSG_DONTWAIT

** on AIX

grep MSG_NONBLOCK /usr/include/sys/socket.h

define MSG_NONBLOCK 0x4000 /* nonblocking request */

[poulacou]

I propose this change
diff --git a/src/modbus-tcp.c b/src/modbus-tcp.c
index 00de11c..5c92743 100644
--- a/src/modbus-tcp.c
+++ b/src/modbus-tcp.c
@@ -440,9 +440,10 @@ static int _modbus_tcp_flush(modbus_t ctx)
do {
/ Extract the garbage from the socket */
char devnull[MODBUS_TCP_MAX_ADU_LENGTH];
-#ifndef OS_WIN32

•    rc = recv(ctx->s, devnull, MODBUS_TCP_MAX_ADU_LENGTH, MSG_DONTWAIT);
  

  -#else
  +#ifdef _AIX

•    rc = recv(ctx->s, devnull, MODBUS_TCP_MAX_ADU_LENGTH, MSG_NONBLOCK);
  

  +#ifdef OS_WIN32
  /* On Win32, it's a bit more complicated to not wait _/
  fd_set rset;
  struct timeval tv;
  @@ -460,6 +461,9 @@ static int modbus_tcp_flush(modbus_t *ctx)
  / There is data to flush */
  rc = recv(ctx->s, devnull, MODBUS_TCP_MAX_ADU_LENGTH, 0);
  }
  +#else

•    rc = recv(ctx->s, devnull, MODBUS_TCP_MAX_ADU_LENGTH, MSG_DONTWAIT);
  

  #endif
  if (rc > 0) {
  rc_sum += rc;

[stephane]

@poulacou what do you think about my patch?

[karlp]

👍

[stephane]

Merged.

[poulacou]

Thanks ;-)

I can't test it for the moment.
It looks ok from a functional point of view

[stephane]

@poulacou I stay tuned, all feedback is always very appreciated.