Re: [PATCH] don't store temporary value returned from c_str()

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+From: Kim Minh Kaplan <kimminh.kaplan+nomuch@afnic.fr>\r
+To: Vladimir Marek <vlmarek@volny.cz>\r
+Subject: Re: [PATCH] don't store temporary value returned from c_str()\r
+References: <1366405933-17223-1-git-send-email-Vladimir.Marek@oracle.com>\r
+       <m2sj2cjp2b.fsf@guru.guru-group.fi>\r
+       <20130427101134.GI10394@pub.cz.oracle.com>\r
+       <8761z4h7ih.fsf@kaki.tech.prive.nic.fr>\r
+       <20130430084852.GA19599@pub.cz.oracle.com>\r
+Date: Tue, 30 Apr 2013 09:44:01 +0000\r
+In-Reply-To: <20130430084852.GA19599@pub.cz.oracle.com> (Vladimir Marek's\r
+       message of "Tue, 30 Apr 2013 10:48:52 +0200")\r
+Message-ID: <87ehdsfj4u.fsf@kaki.tech.prive.nic.fr>\r
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+Cc: Tomi Ollila <tomi.ollila@iki.fi>, notmuch@notmuchmail.org\r
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+\r
+Vladimir Marek=C2=A0:\r
+\r
+> Thank you, I found it eventually too. But I wrote little test program\r
+> (attached) which confused me. I haven't had much time to take a look\r
+> into it since weekend.\r
+>\r
+> The idea is to have temporary object where I can detect whether\r
+> destructor was called.\r
+>\r
+> I thought that\r
+>\r
+> printf ("%s\n", s.c_str());\r
+> will print "test"\r
+>\r
+> and\r
+>\r
+> x=3Ds.c_str();\r
+> printf ("%s\n", x);\r
+>\r
+> will print "destroyed"\r
+>\r
+> On my machine both prints "destroyed".\r
+\r
+You have to somehow instantiate a temporary object, using a function\r
+call for example.\r
+\r
+    #include <string.h>\r
+    #include <stdio.h>\r
+    struct example {\r
+      char data[10];\r
+      char *c_str() { return data; }\r
+     example() { strcpy(data, "test"); }\r
+      ~example() { strcpy(data, "destroyed"); }\r
+    };\r
+    example foo()\r
+    {\r
+      example res;\r
+      return res;\r
+    }\r
+    main()\r
+    {\r
+      printf("%s\n", foo().c_str());\r
+      char *x =3D foo().c_str();\r
+      printf("%s\n", x);\r
+    }\r
+\r
+Kim Minh.\r