X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=ext%2FIO%2FIO.xs;h=be84f732686bcf42f9fa67004a0459d1655a305c;hb=6fd254a478c7f8019c24fcc4c32de680d740e450;hp=e5ce83d94877d1ecba527acdc18478a170fbb76d;hpb=b5db9eb702378f2c90dfe7971e188db541df3456;p=p5sagit%2Fp5-mst-13.2.git

diff --git a/ext/IO/IO.xs b/ext/IO/IO.xs
index e5ce83d..be84f73 100644
--- a/ext/IO/IO.xs
+++ b/ext/IO/IO.xs
@@ -62,23 +62,28 @@ io_blocking(InputStream f, int block)
 	/* POSIX style */ 
 #if defined(O_NDELAY) && O_NDELAY != O_NONBLOCK
 	/* Ooops has O_NDELAY too - make sure we don't 
-	 * get SysV behaviour by mistake
-	 */
-	RETVAL = RETVAL & O_NONBLOCK ? 0 : 1;
-
-	if ((mode & O_NDELAY) || ((block == 0) && !(mode & O_NONBLOCK))) {
-	    int ret;
-	    mode = (mode & ~O_NDELAY) | O_NONBLOCK;
-	    ret = fcntl(PerlIO_fileno(f),F_SETFL,mode);
-	    if(ret < 0)
-		RETVAL = ret;
-	}
-	else if ((mode & O_NDELAY) || ((block > 0) && (mode & O_NONBLOCK))) {
-	    int ret;
-	    mode &= ~(O_NONBLOCK | O_NDELAY);
-	    ret = fcntl(PerlIO_fileno(f),F_SETFL,mode);
-	    if(ret < 0)
-		RETVAL = ret;
+	 * get SysV behaviour by mistake. */
+
+	/* E.g. In UNICOS and UNICOS/mk a F_GETFL returns an O_NDELAY
+	 * after a successful F_SETFL of an O_NONBLOCK. */
+	RETVAL = RETVAL & (O_NONBLOCK | O_NDELAY) ? 0 : 1;
+
+	if (block >= 0) {
+	    if ((mode & O_NDELAY) || ((block == 0) && !(mode & O_NONBLOCK))) {
+	        int ret;
+	        mode = (mode & ~O_NDELAY) | O_NONBLOCK;
+	        ret = fcntl(PerlIO_fileno(f),F_SETFL,mode);
+	        if(ret < 0)
+		    RETVAL = ret;
+	    }
+	    else
+              if ((mode & O_NDELAY) || ((block > 0) && (mode & O_NONBLOCK))) {
+	        int ret;
+	        mode &= ~(O_NONBLOCK | O_NDELAY);
+	        ret = fcntl(PerlIO_fileno(f),F_SETFL,mode);
+	        if(ret < 0)
+		    RETVAL = ret;
+              }
 	}
 #else
 	/* Standard POSIX */