fcntl lockfile example

c/fcntl_ex/fcntl_lockfile.c

@@ -0,0 +1,62 @@
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <linux/fcntl.h>
+#include <stdio.h>
+#include <sys/file.h>
+#include <unistd.h>
+#include <signal.h>
+#include <err.h>
+#include <errno.h>
+
+void sighandler(int signum)
+{
+	printf("signal %d received\n", signum);
+}
+
+int main()
+{
+/* не работает с nfs
+	FILE *f = fopen("fcntl_lockfile.c", "wb");
+
+	if(f != NULL && !flock(fileno(f), LOCK_EX | LOCK_NB))// !ftrylockfile(f))
+		puts("Success!");
+
+	else
+		puts("Failed!");
+
+	getchar();
+
+	return 0;
+*/
+
+/* 1 процесс
+	FILE *f = fopen("fcntl_lockfile.c", "wb");
+
+	if(f != NULL && !ftrylockfile(f)) {
+		flockfile(f);
+		puts("Success!");
+
+	} else
+		puts("Failed!");
+
+	getchar();
+
+	return 0;
+*/
+
+	signal(SIGPOLL, sighandler);
+
+	int fd = open("fcntl_lockfile.c", O_RDWR | O_NONBLOCK);
+
+	if (fd == -1)
+		err(errno, "open()");
+
+	if (fcntl(fd, F_SETLEASE, F_WRLCK) == -1)
+		err(errno, "fcntl()");
+
+	puts("Success!");
+
+	getchar();
+
+	return 0;
+}