diff --git a/src/Composer/Command/CreateProjectCommand.php b/src/Composer/Command/CreateProjectCommand.php
index 1801583fd..067fb9a40 100644
--- a/src/Composer/Command/CreateProjectCommand.php
+++ b/src/Composer/Command/CreateProjectCommand.php
@@ -362,7 +362,7 @@ EOT
         }
 
         // handler Ctrl+C for unix-like systems
-        if (function_exists('pcntl_async_signals')) {
+        if (function_exists('pcntl_async_signals') && function_exists('pcntl_signal')) {
             @mkdir($directory, 0777, true);
             if ($realDir = realpath($directory)) {
                 pcntl_async_signals(true);
diff --git a/src/Composer/Command/RequireCommand.php b/src/Composer/Command/RequireCommand.php
index cbdfdaf9c..9b59e7feb 100644
--- a/src/Composer/Command/RequireCommand.php
+++ b/src/Composer/Command/RequireCommand.php
@@ -84,7 +84,7 @@ EOT
 
     protected function execute(InputInterface $input, OutputInterface $output)
     {
-        if (function_exists('pcntl_async_signals')) {
+        if (function_exists('pcntl_async_signals') && function_exists('pcntl_signal')) {
             pcntl_async_signals(true);
             pcntl_signal(SIGINT, array($this, 'revertComposerFile'));
             pcntl_signal(SIGTERM, array($this, 'revertComposerFile'));