IPC : added some bugs

code/Makefile

@@ -19,5 +19,17 @@ arguments:	arguments.c Makefile
 no-op:		no-op.c Makefile
 	gcc -Wall $< -o $@
 
+#------------- IPC
+
 get-signal:	get-signal.c Makefile
 	gcc -Wall $< -o $@
+
+dtime.o:	dtime.c my-fifo.h Makefile
+	gcc -Wall -c $<
+
+fifo-tx:	fifo-tx.c my-fifo.h dtime.o Makefile
+	gcc -Wall $< dtime.o -o $@
+
+fifo-rx:	fifo-rx.c my-fifo.h dtime.o Makefile
+	gcc -Wall $< dtime.o -o $@
+

code/dtime.c

@@ -0,0 +1,9 @@
+#include <stddef.h>
+#include <sys/time.h>
+
+double dtime(void)
+{
+struct timeval tv;
+gettimeofday(&tv, NULL);
+return (double)tv.tv_sec + ((double)tv.tv_usec)/1e6;
+}

code/fifo-rx.c

@@ -0,0 +1,27 @@
+/***		named pipe --- receiver		***/
+
+#include  <stdio.h>
+#include  <stdlib.h>
+#include  <unistd.h>
+#include  <sys/stat.h>		/* for mkfifo */
+#include  <fcntl.h>
+#include  "my-fifo.h"
+
+int main(int argc, char *argv[])
+{
+int		fifo;
+Message		message;
+double		localTS;
+
+if (argc!=2)		exit(1);
+fifo = mkfifo(argv[1], 0400);
+if (fifo) {
+	perror("mkfifo fail");
+	exit(2);
+	}
+read(fifo, &message, sizeof(Message));
+localTS = dtime();
+printf("%f  %f\n", localTS, message.timestamp);
+close(fifo);
+return 0;
+}

code/fifo-tx.c

@@ -0,0 +1,24 @@
+/***		named pipe --- transmiter	***/
+#include  <stdio.h>
+#include   <stdlib.h>
+#include  <unistd.h>
+#include  <fcntl.h>
+#include  "my-fifo.h"
+
+int main(int argc, char *argv[])
+{
+int		fifo;
+Message		message;
+
+if (argc!=2)		exit(1);
+if (-1==(fifo = open(argv[1], O_WRONLY))) {
+	perror("open fifo for wr");
+	exit(1);
+	}
+message.pid = getpid();
+message.timestamp = dtime();
+write(fifo, &message, sizeof(Message));
+close(fifo);
+
+return 0;
+}

code/my-fifo.h

@@ -0,0 +1,7 @@
+typedef struct {
+	int		pid;
+	double		timestamp;
+	long		notused;
+	} Message;
+
+double dtime(void);