the signature of getopt, and getopt_long

[Lorenzo Bettini]

Hi

I'm the author and maintainer of GNU gengetopt, 
http://www.gnu.org/software/gengetopt/, which generates a C function 
that uses getopt_long function to parse the command line options, to 
validate them and fills a struct.

I'm using gnulib's getopt module to make gengetopt compilable also on 
systems without a (possibly correct implementation of) getopt functions.

gengetopt generates a function with the signature

int cmdline_parser (int argc, char * const *argv,
  struct gengetopt_args_info *args_info);

because it mimic the

char * const *argv

libc declaration of getopt_long (which looks wrong, since argv might be 
changed during the parsing, right?)

when compiling the generated parser using the gnulib version I get the 
warnings

warning: passing argument 2 of 'rpl_getopt_long' discards qualifiers 
from pointer target type

since the gnulib version declares it like this

getopt_long (int ___argc, char *__getopt_argv_const *___argv,
                        const char *__shortopts,
                        const struct option *__longopts, int *__longind)

now, I'd like to avoid the warning in the generated parser when using 
gnulib, but I'd like to avoid it also when using libc getopt_long version...

what would you suggest?

change my generated function signature to

int cmdline_parser (int argc, char **argv,
  struct gengetopt_args_info *args_info);

and then, internally perform a cast to

char *__getopt_argv_const *___argv

before invoking getopt_long?

many thanks in advance
        Lorenzo

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Lorenzo Bettini, PhD in Computer Science, DI, Univ. Torino
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