Re: Removing GCC warnings from flex- and bison- generated C code

Paul Eggert <eggert@twinsun.com>
12 Jan 2004 12:40:30 -0500

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Related articles
Removing GCC warnings from flex- and bison- generated C code zender@uci.edu (Charlie Zender) (2004-01-09)
Re: Removing GCC warnings from flex- and bison- generated C code eggert@twinsun.com (Paul Eggert) (2004-01-12)
Re: Removing GCC warnings from flex- and bison- generated C code zender@uci.edu (Charlie Zender) (2004-01-16)
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From: Paul Eggert <eggert@twinsun.com>
Newsgroups: comp.compilers
Date: 12 Jan 2004 12:40:30 -0500
Organization: Compilers Central
References: 04-01-045
Keywords: yacc
Posted-Date: 12 Jan 2004 12:40:30 EST

At 9 Jan 2004 23:49:52 -0500, Charlie Zender <zender@uci.edu> writes:


> ncap_yacc.c:1216: warning: implicit declaration of function `yylex'


This indicates a minor bug in your parser's C code. Your parser is
supposed to declare 'yylex' (presumably in a file that your parser
includes), but it hasn't done so.


In traditional C and C89, 'yylex' didn't need to be declared, since it
is a function that returns 'int'. But C99 requires that such
functions be declared, and you are using a pedantic C99 compiler.


There's often a similar problem with 'yyerror'.


This is the only problem you had with Bison. I didn't look at your
Flex problems in detail, but many of them appear to be similar.




> [I hope this is on topic, if not where should I send it?]


Please send Bison bug reports to <bug-bison@gnu.org>.
For Flex please see <http://lex.sourceforge.net/>.


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