--- ray/src/util/rpiece.c	1992/08/07 11:05:30	2.5
+++ ray/src/util/rpiece.c	1992/08/08 18:47:39	2.7
@@ -10,6 +10,7 @@ static char SCCSid[] = "$SunId$ LBL";
  
 #include "standard.h"
 #include <fcntl.h>
+#include <signal.h>
 #include "color.h"
 #include "view.h"
 #include "resolu.h"
@@ -35,7 +36,10 @@ int  verbose = 0;
 
 extern long  lseek(), ftell();
 
+int  gotalrm = 0;
+int  onalrm() { gotalrm++; }
 
+
 main(argc, argv)
 int  argc;
 char  *argv[];
@@ -168,7 +172,6 @@ char  **av;
 	scanorig = ftell(fp);		/* record position of first scanline */
 	if (fclose(fp) == -1)		/* done with stream i/o */
 		goto filerr;
-	sync();				/* avoid NFS buffering */
 					/* start rpict process */
 	if (open_process(rpd, rpargv) <= 0) {
 		fprintf(stderr, "%s: cannot start %s\n", progname, rpargv[0]);
@@ -184,6 +187,7 @@ char  **av;
 		fprintf(stderr, "%s: out of memory\n", progname);
 		exit(1);
 	}
+	signal(SIGALRM, onalrm);
 	return;
 filerr:
 	fprintf(stderr, "%s: file i/o error\n", outfile);
@@ -199,7 +203,9 @@ int  *xp, *yp;
 	struct flock  fls;
 	char  buf[64];
 
-	if (syncfd != -1) {		/* using sync file */
+	if (gotalrm)			/* someone wants us to quit */
+		return(0);
+	if (syncfd != -1) {		/* use sync file */
 		fls.l_type = F_WRLCK;		/* gain exclusive access */
 		fls.l_whence = 0;
 		fls.l_start = 0L;
@@ -225,7 +231,7 @@ int  *xp, *yp;
 		fcntl(syncfd, F_SETLKW, &fls);
 		return(1);
 	}
-	if (fgets(buf, sizeof(buf), stdin) == NULL)	/* using stdin */
+	if (fgets(buf, sizeof(buf), stdin) == NULL)	/* use stdin */
 		return(0);
 	if (sscanf(buf, "%d %d", xp, yp) == 2)
 		return(1);
@@ -297,6 +303,7 @@ rpiece()			/* render picture piece by piece */
 putpiece(xpos, ypos)		/* get next piece from rpict */
 int  xpos, ypos;
 {
+	struct flock  fls;
 	int  hr, vr;
 	int  y;
 
@@ -312,6 +319,9 @@ int  xpos, ypos;
 				progname, rpargv[0]);
 		exit(1);
 	}
+	fls.l_whence = 1;
+	fls.l_start = 0L;
+	fls.l_len = hr*sizeof(COLR);
 	for (y = 0; y < vr; y++) {	/* transfer scanlines */
 		if (freadcolrs(scanline, hr, fromrp) < 0) {
 			fprintf(stderr, "%s: read error from %s\n",
@@ -324,10 +334,14 @@ scanorig+((long)((vmult-1-ypos)*vres+y)*hmult*hres+xpo
 			fprintf(stderr, "%s: seek error\n", outfile);
 			exit(1);
 		}
+		fls.l_type = F_WRLCK;
+		fcntl(outfd, F_SETLKW, &fls);
 		if (writebuf(outfd, (char *)scanline, hr*sizeof(COLR)) !=
 				hr*sizeof(COLR)) {
 			fprintf(stderr, "%s: write error\n", outfile);
 			exit(1);
 		}
+		fls.l_type = F_UNLCK;
+		fcntl(outfd, F_SETLKW, &fls);
 	}
 }