Fix protection of asynch I/O feature.

* NEC SX might not be the only platform without asynchronous I/O facilities.
* Also fix problem where the feature is available at compile time but
  not enabled at run-time.

src/pio_impl.h

@@ -6,6 +6,7 @@
 #endif
 
 #include <stdbool.h>
+#include <unistd.h>
 
 #include <mpi.h>
 
@@ -101,7 +102,7 @@ void cdiPioFileWriteAtReblockInit(const struct cdiPioConf *conf);
 void pioSendInitialize(void);
 
 /* pio_posixasynch.c */
-#ifndef _SX
+#ifdef _POSIX_ASYNCHRONOUS_IO
 void pioWriterAIO(void);
 #endif
 

src/pio_interface.c

@@ -7,6 +7,7 @@
 #include <stdbool.h>
 #include <stdlib.h>
 #include <stdio.h>
+#include <unistd.h>
 
 #include <mpi.h>
 #include <yaxt.h>
@@ -414,9 +415,12 @@ cdiPioInit(MPI_Comm commGlob, int confResH, int *pioNamespace)
 
   if (IOMode < PIO_MINIOMODE || IOMode > PIO_MAXIOMODE) xabort("IOMODE IS NOT VALID.");
 
-#ifdef _SX
-  if (IOMode == PIO_ASYNCH) xabort("PIO_ASYNCH DOES NOT WORK ON SX.");
+  if (
+#ifdef _POSIX_ASYNCHRONOUS_IO
+      !sysconf(_SC_ASYNCHRONOUS_IO) &&
 #endif
+      IOMode == PIO_ASYNCH)
+    xabort("CDI-PIO Output method PIO_ASYNCH is unsupported on this system!");
 
   if ((xtInitByCDI = (!xt_initialized() || xt_finalized()))) xt_initialize(commGlob);
   int nProcsIO = cdiPioCommInit(commGlob, IOMode, conf->clientServerRole);
@@ -488,9 +492,7 @@ cdiPioFileWritingInit(const struct cdiPioConf *conf)
     {
     case PIO_NONE: break;
     case PIO_MPI: initMPINONB(); break;
-#ifndef _SX
     case PIO_ASYNCH:
-#endif
     case PIO_WRITER: pioSendInitialize(); break;
     case PIO_FPGUARD: initPOSIXFPGUARDSENDRECV(); break;
     case PIO_MPI_FW_ORDERED: cdiPioFileWriteOrderedInit(); break;

src/pio_posixasynch.c

@@ -6,8 +6,9 @@
 #include "config.h"
 #endif
 
-#ifndef _SX
+#include <unistd.h>
 
+#ifdef _POSIX_ASYNCHRONOUS_IO
 #include <aio.h>
 #include <errno.h>
 #include <fcntl.h>
@@ -16,7 +17,6 @@
 #include <string.h>
 #include <sys/types.h>
 #include <sys/stat.h>
-#include <unistd.h>
 
 #include <mpi.h>
 

src/pio_record_send.c

@@ -4,6 +4,7 @@
 
 #include <inttypes.h>
 #include <stdlib.h>
+#include <unistd.h>
 
 #include "cdipio.h"
 #include "dmemory.h"
@@ -289,7 +290,9 @@ pioSendInitialize(void)
   if (!isCollector) switch (commInqIOMode())
       {
       case PIO_WRITER: pioWriterStdIO(); break;
+#ifdef _POSIX_ASYNCHRONOUS_IO
       case PIO_ASYNCH: pioWriterAIO(); break;
+#endif
       }
   else
     {