Re: Memory leak in bison-generated code

[Hans Aberg]

On 6 Feb 2009, at 17:54, Jean Delvare wrote:

> Valgrind tells me that there's a memory leak in libsensors [1], in  
> code
> which is generated by flex/bison:
...
> I upgraded to bison 2.4.1. Alas, the memory leak is still there, and  
> as
> a matter of fact I don't see any call to  yylex_destroy() in the
> generated code. If I do call sensors_yylex_destroy() manually then the
> memory leak goes away.

Bison is just a parser generator, and though it should be synced with  
Flex, it is a different project, and things like lexer allocation/ 
deallocation must be handled by hand or within the lexer (your leaks  
looks being within the lexer). Since the problem goes away if you call  
sensors_yylex_destroy() manually, it might be a Bison documentation  
problem.

On the other hand, a FAQ is figuring out how to do token allocation,  
and then, when using C, one has to deallocate it by hand in every  
rule. So if you have ideas to fix it, you might report it on the Bug- 
Bison list.

  Hans