1 files changed, 87 insertions, 0 deletions
diff --git a/errno.c b/errno.c
new file mode 100644
index 0000000..e6cf5e7
--- /dev/null
+++ b/errno.c
@@ -0,0 +1,87 @@
+/*
+ * errno.c
+ *
+ * Description:
+ * This translation unit implements routines associated with spawning a new
+ * thread.
+ *
+ * Pthreads-win32 - POSIX Threads Library for Win32
+ * Copyright (C) 1998
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the Free
+ * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
+ * MA 02111-1307, USA
+ */
+
+#if defined( _REENTRANT ) || defined( _MT )
+
+#include "pthread.h"
+#include "implement.h"
+
+static int reallyBad    = ENOMEM;
+
+/*
+ * Re-entrant errno.
+ *
+ * Each thread has it's own errno variable in pthread_t.
+ *
+ * The benefit of using the pthread_t structure
+ * instead of another TSD key is TSD keys are limited
+ * on Win32 to 64 per process. Secondly, to implement
+ * it properly without using pthread_t you'd need
+ * to dynamically allocate an int on starting the thread
+ * and store it manually into TLS and then ensure that you free
+ * it on thread termination. We get all that for free
+ * by simply storing the errno on the pthread_t structure.
+ *
+ * Relies on the following being defined in errno.h:
+ * (true for MSVC and Mingw32 I think)
+ *
+ * #if defined( _REENTRANT ) || defined( _MT )
+ * #define errno *_errno()
+ * 
+ * int *_errno( void );
+ * #else
+ * extern int errno;
+ * #endif /* _REENTRANT */
+ *
+ */
+
+int * _errno( void )
+{
+  pthread_t       *self;
+  int             *result;
+        
+  if( ( self = pthread_self() ) == NULL )
+    {
+      /*
+       * Yikes! unable to allocate a thread!
+       * Throw an exception? return an error?
+       */
+      result = &reallyBad;
+    }
+  else
+    {
+      result = &(self->ptErrno);
+    }
+
+  return( result );
+
+} /* _errno */
+
+#else
+
+#error "errno: Not thread-safe."
+
+#endif /* _REENTRANT || _MT */