CODEWITHSUNDEEP
memorybisonflex-lexer
dennisg
dennisg

Reputation: 1

How to use my own implementation for malloc, realloc and free inside bison+flex?

I am using bison + flex to write a parser now.

For bison and flex, the generated parser and scanner manage their memory with malloc, realloc and free.

But I want to use my own implementation for malloc, realloc and free inside bison + flex.

According to another post:

Being C, the generated parser and scanner manage their memory with malloc, realloc and free. They are good enough to expose hooks allowing me to submit my own implementations of these functions.

Where are those hooks and how do I use them?

Upvotes: 0

Views: 707

Answers (1)

rici
rici

Reputation: 241911

The flex overrides are described in the flex manual. In summary, you need to define the functions yyalloc, yyfree and yyrealloc (whose prototypes are unsurprising, but read the manual if you are using a reentrant scanner), and also tell flex not to generate the functions:

%option noyyalloc noyyfree noyyrealloc

For bison, if you are using the standard C skeleton, you can define the macros YYMALLOC and YYFREE, whose default values are malloc and free. bison does not (by default) use realloc. I presume this is not documented because it is dependent on the skeleton used.

Upvotes: 0

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