update c greet function to return string instead of write to stdout.main

3 files changed, 13 insertions, 6 deletions

diff --git a/greeting.c b/greeting.c
index 1a105e9..0543a0a 100644
--- a/greeting.c
+++ b/greeting.c
@@ -1,11 +1,19 @@
 #include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
 
-void greet(char *name) {
-  printf("Hello %s\n", name);
+static const char* alias_name = "ALTER_EGO";
+
+char* greet(char* name) {
+  char* alias = getenv(alias_name);
+  char* buffer = (char*)malloc(128);
+  snprintf(buffer, 128, "Hello %s!\n", alias == NULL ? name : alias);
+  return buffer;
 }
 
 int main(int argc, const char *argv[])
 {
-  greet("mo");
+  printf("%s\n", greet("mo"));
   return 0;
 }
diff --git a/greeting.h b/greeting.h
index 1533b88..3668e40 100644
--- a/greeting.h
+++ b/greeting.h
@@ -1,2 +1 @@
-
 void greet(char *name);
diff --git a/greeting.rb b/greeting.rb
index d5ddf44..a0b31a2 100644
--- a/greeting.rb
+++ b/greeting.rb
@@ -3,7 +3,7 @@ require 'ffi'
 class Greeting
   extend FFI::Library
   ffi_lib 'greeting'
-  attach_function :greet, [:string], :int
+  attach_function :greet, [:string], :string
 end
 
-Greeting.greet('mo')
+puts Greeting.greet('mo')