chore: import upstream snapshot with attribution

examples/c/Makefile

@@ -0,0 +1,13 @@
+SRCS = $(wildcard *.c)
+
+PROGS = $(patsubst %.c,%,$(SRCS))
+
+all: $(PROGS)
+
+%: %.c
+	$(CC) $(CFLAGS) -o $@ $<
+
+clean: 
+	rm -f $(PROGS)
+
+.PHONY: all clean

examples/c/env.c

@@ -0,0 +1,12 @@
+#include <stdio.h>
+  
+// Most of the C compilers support a third parameter to main which
+// store all envorinment variables
+int main(int argc, char *argv[], char * envp[])
+{
+    int i;
+    for (i = 0; envp[i] != NULL; i++)
+        printf("\n%s", envp[i]);
+    getchar();
+    return 0;
+}

examples/c/helloworld.c

@@ -0,0 +1,6 @@
+#include <stdio.h>
+
+int main()
+{
+	printf("Hello, World!\n");
+}

examples/c/link.c

@@ -0,0 +1,7 @@
+#include <unistd.h>
+
+int main()
+{
+	link("env", "env3");
+	return 0;
+}

examples/c/openat.c

@@ -0,0 +1,10 @@
+#include <fcntl.h>
+#include <stdio.h>
+#include <errno.h>
+
+int main()
+{
+	int ret = openat(AT_FDCWD, "/dev/tty", 0x88102, 0);
+	printf("return value is %d and errno is %d\n", ret, errno);
+}
+

examples/c/waitpid.c

@@ -0,0 +1,17 @@
+#include <sys/wait.h>
+#include <unistd.h>
+#include <errno.h>
+#include <stdio.h>
+
+int main()
+{
+	int status;
+
+	pid_t p = getpid();
+	// waitpid takes a children's pid, not the current process one
+	// if the pid is not a children of the current process, it returns -ECHILD
+	pid_t res = waitpid(1001, &status, WNOHANG);
+
+	printf("res is %d, p is %d and errno is %d\n", res, p, errno);
+
+}