X-Git-Url: https://www.ginac.de/ginac.git//ginac.git?p=ginac.git;a=blobdiff_plain;f=ginac%2Fptr.h;h=89bb1d4ae9b62a25ed8e7ad649871991d2d26378;hp=93b16416f5471d9bd9eb165fd7d159767a3f2522;hb=18d403808b2c0fd73f43cbf4e346c5902f052a65;hpb=0a5049a0354466a88862c67b1b9c9e27e36cc309

diff --git a/ginac/ptr.h b/ginac/ptr.h
index 93b16416..89bb1d4a 100644
--- a/ginac/ptr.h
+++ b/ginac/ptr.h
@@ -3,7 +3,7 @@
  *  Reference-counted pointer template. */
 
 /*
- *  GiNaC Copyright (C) 1999-2003 Johannes Gutenberg University Mainz, Germany
+ *  GiNaC Copyright (C) 1999-2007 Johannes Gutenberg University Mainz, Germany
  *
  *  This program is free software; you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
@@ -17,7 +17,7 @@
  *
  *  You should have received a copy of the GNU General Public License
  *  along with this program; if not, write to the Free Software
- *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
  */
 
 #ifndef __GINAC_PTR_H__
@@ -80,11 +80,14 @@ public:
 
 	ptr &operator=(const ptr & other)
 	{
-		// NB: must first add reference to "other", since other might be *this.
-		other.p->add_reference();
+		// NB1: Must first add reference to "other", since other might be *this.
+		// NB2: Cache other.p, because if "other" is a subexpression of p,
+		//      deleting p will also invalidate "other".
+		T *otherp = other.p;
+		otherp->add_reference();
 		if (p->remove_reference() == 0)
 			delete p;
-		p = other.p;
+		p = otherp;
 		return *this;
 	}
 
@@ -139,6 +142,7 @@ public:
 	inline friend std::ostream & operator<<(std::ostream & os, const ptr<T> & rhs)
 	{
 		os << rhs.p;
+		return os;
 	}
 
 private: