declaration error trying to use flex with c++

hedpe · 03-30-2009, 01:22 PM

Hi all,

I am trying to build an architecture simulator (http://cva.stanford.edu/books/ppin/#sim) that uses flex with bison to generate some code. I'm not extremely familiar with either tool. It first uses flex to generate configlex.cpp from config.l:

Code:

flex -Pconfig -oconfiglex.cpp config.l

Here is config.l and configlex.cpp, respectively:
http://pastebin.com/f746a6b77
http://pastebin.com/f598c894e

Line 18 in config.l has:

Code:

unsigned int configlineno = 1;

After flex runs, configlex.cpp generates:

Code:

extern int configlineno; // line 361
int configlineno = 1; // line 363unsigned int configlineno = 1; // line 493

This obviously creates a problem when it tries to build:

Code:

config.l:18: error: conflicting declaration ‘unsigned int configlineno’
configlex.cpp:363: error: ‘configlineno’ has a previous declaration as ‘int configlineno’

Why does it generate both an int and an unsigned int? I would appreciate any feedback.

Thanks!
George

hedpe · 03-30-2009, 07:15 PM

fixed, apparently <prefix>lineno is an internal flex variable name