Nut upsdev - Jan 2011 - [nut-commits] svn commit r2845 - branches/windows_port/common

On mar., 2011-01-18 at 19:52 +0000, Arjen de Korte
wrote:
> Author: adkorte-guest
> Date: Tue Jan 18 19:52:02 2011
> New Revision: 2845
> URL: http://trac.networkupstools.org/projects/nut/changeset/2845
> 
> Log:
> Prefer to use static variables locally over global variables (to prevent
namespace conflicts)
> 
> Modified:
>    branches/windows_port/common/common.c
> 
> Modified: branches/windows_port/common/common.c
>
=============================================================================>
--- branches/windows_port/common/common.c	Tue Jan 18 15:40:58 2011	(r2844)
> +++ branches/windows_port/common/common.c	Tue Jan 18 19:52:02 2011	(r2845)
> @@ -41,11 +41,6 @@
>  	int	nut_log_level = 0;
>  	static	int	upslog_flags = UPSLOG_STDERR;
>  
> -#ifdef WIN32
> -const char * relative_conf_path = NULL;
> -const char * relative_state_path = NULL;
> -#endif
> -
>  static void xbit_set(int *val, int flag)
>  {
>  	*val |= flag;
> @@ -440,51 +435,25 @@
>  
> 
>  /* Return the default path for the directory containing configuration
files */
> -const char * confpath(void) 
> +const char * confpath(void)
>  {
> -	const char * path;
> -
> -	if ((path = getenv("NUT_CONFPATH")) == NULL) {
>  #ifndef WIN32
> -		path = CONFPATH;
> +	const char *path = getenv("NUT_CONFPATH");
>  #else
> -		if( relative_conf_path == NULL ) {
> -			path = getfullpath(PATH_ETC);
> -			if( path == NULL ) {
> -				path = CONFPATH;
> -			}
> -		}
> -		else {
> -			path = relative_conf_path;
> -		}
> +	static const char *path = getfullpath(PATH_ETC);
getfullpath is allocating memory with xstrdup. Doesn't this line produce
a memory leak ?


>  #endif
> -	}
> -
> -	return path;
> +	return (path != NULL) ? path : CONFPATH;
>  }
>  
>  /* Return the default path for the directory containing state files */
> -const char * dflt_statepath(void) 
> +const char * dflt_statepath(void)
>  {
> -	const char * path;
> -
> -	if ((path = getenv("NUT_STATEPATH")) == NULL) {
>  #ifndef WIN32
> -		path = STATEPATH;
> +	const char *path = getenv("NUT_STATEPATH");
>  #else
> -		if( relative_state_path == NULL ) {
> -			path = getfullpath(PATH_VAR_RUN);
> -			if( path == NULL ) {
> -				path = STATEPATH;
> -			}
> -		}
> -		else {
> -			path = relative_state_path;
> -		}
> +	static const char *path = getfullpath(PATH_VAR_RUN);
>  #endif
> -	}
> -
> -	return path;
> +	return (path != NULL) ? path : STATEPATH;
>  }
>  
>  /* Return the alternate path for pid files */
> 
> _______________________________________________
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> nut-commits at lists.alioth.debian.org
> http://lists.alioth.debian.org/mailman/listinfo/nut-commits

--------------------------------------------------------------------------

Citeren Fr?d?ric Boh? <fredericbohe op eaton.com>:
>> +	static const char *path = getfullpath(PATH_ETC);
>
> getfullpath is allocating memory with xstrdup. Doesn't this line
produce
> a memory leak ?
Nope.

Whenever you do an assignment to a static variable, this is only done  
once. So the getfullpath() function will be called the first time you  
enter this function and afterwards, the result of this call will be  
used. Unlike an ordinary automatic variable, static variables defined  
in functions are preserved between calls.

We usually prefer static local variables over global ones, because it  
prevents namespace conflicts and also prevents other function from  
messing with the variables.

Best regards, Arjen
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