doc: add code samples from uvbook (unadapted)

PR-URL: https://github.com/libuv/libuv/pull/1246
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Santiago Gimeno <santiago.gimeno@gmail.com>

3 files changed, 51 insertions, 0 deletions

diff --git a/docs/code/plugin/hello.c b/docs/code/plugin/hello.c
new file mode 100644
index 00000000..7b2861d7
--- /dev/null
+++ b/docs/code/plugin/hello.c
@@ -0,0 +1,5 @@
+#include "plugin.h"
+
+void initialize() {
+    mfp_register("Hello World!");
+}
diff --git a/docs/code/plugin/main.c b/docs/code/plugin/main.c
new file mode 100644
index 00000000..06e581e6
--- /dev/null
+++ b/docs/code/plugin/main.c
@@ -0,0 +1,39 @@
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+
+#include <uv.h>
+
+#include "plugin.h"
+
+typedef void (*init_plugin_function)();
+
+void mfp_register(const char *name) {
+    fprintf(stderr, "Registered plugin \"%s\"\n", name);
+}
+
+int main(int argc, char **argv) {
+    if (argc == 1) {
+        fprintf(stderr, "Usage: %s [plugin1] [plugin2] ...\n", argv[0]);
+        return 0;
+    }
+
+    uv_lib_t *lib = (uv_lib_t*) malloc(sizeof(uv_lib_t));
+    while (--argc) {
+        fprintf(stderr, "Loading %s\n", argv[argc]);
+        if (uv_dlopen(argv[argc], lib)) {
+            fprintf(stderr, "Error: %s\n", uv_dlerror(lib));
+            continue;
+        }
+
+        init_plugin_function init_plugin;
+        if (uv_dlsym(lib, "initialize", (void **) &init_plugin)) {
+            fprintf(stderr, "dlsym error: %s\n", uv_dlerror(lib));
+            continue;
+        }
+
+        init_plugin();
+    }
+
+    return 0;
+}
diff --git a/docs/code/plugin/plugin.h b/docs/code/plugin/plugin.h
new file mode 100644
index 00000000..21f194e6
--- /dev/null
+++ b/docs/code/plugin/plugin.h
@@ -0,0 +1,7 @@
+#ifndef UVBOOK_PLUGIN_SYSTEM
+#define UVBOOK_PLUGIN_SYSTEM
+
+// Plugin authors should use this to register their plugins with mfp.
+void mfp_register(const char *name);
+
+#endif