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From:	Ross Smith <rosss AT pharos DOT co DOT nz>
To:	"'Hans Werner Strube'" <strube AT physik3 DOT gwdg DOT de>, cygwin AT cygwin DOT com
Subject:	RE: putenv uses volatile memory
Date:	Tue, 13 Aug 2002 09:13:18 +1200
MIME-Version:	1.0

> From: Hans Werner Strube [mailto:strube AT physik3 DOT gwdg DOT de]
> 
> Cygwin version: 1.3.12-2.
> Function putenv() obviously stores only the address of the argument
> string, not its contents. Thus it works reliably only for 
> static, unchanged
> argument strings. Consider the command sequence
>         char env[256];
>         strcpy(env,"EINS=one");
>         putenv(env);
>         strcpy(env,"ZWEI=two");
> /*      putenv(env);*/
> With or without the last putenv(), only the environment ZWEI=two
> exists now, the first one has been overwritten.

This is correct behaviour according to the Single Unix Standard:
http://www.opengroup.org/onlinepubs/007904975/functions/putenv.html

> Workaround: #define putenv(x) putenv(strdup(x))

Does the phrase "memory leak" suggest anything to you? :-)

-- 
Ross Smith ...................... Pharos Systems, Auckland, New Zealand

"C++ is to programming as sex is to reproduction. Better ways might
technically exist but they're not nearly as much fun." - Nikolai Irgens
 

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