/** droptxx_example.cpp
*
* A simple dropt example.
*
* Written by James D. Lin and assigned to the public domain.
*
* The latest version of this file can be downloaded from:
*
*/
#include
#include
#include
#include
#include
#include "droptxx.hpp"
typedef enum { unknown, heads, tails } face_type;
/* Function prototype for our custom function to parse a string to a face_type. */
static dropt_option_handler_decl handle_face;
int
main(int argc, char** argv)
{
bool showHelp = 0;
bool showVersion = 0;
int i = 0;
face_type face = unknown;
/* Each option is defined by a row in a table, containing properties
* such as the option's short name (e.g. -h), its long name (e.g.
* --help), its help text, its handler callback, and its callback data
* (for typical handlers, this data is usually the address of a variable
* for the handler to modify).
*
* See the dropt_option documentation in dropt.h for a complete list
* of option properties.
*
* The table alternatively can be formed by adding options explicitly
* as shown below:
*/
dropt_option emptyOpt = { };
dropt_option opt;
std::vector options;
opt = emptyOpt;
opt.short_name = 'h';
opt.long_name = "help";
opt.handler = dropt::handle_bool;
opt.handler_data = &showHelp;
opt.attr = dropt_attr_halt;
options.push_back(opt);
opt.short_name = '?';
opt.long_name = NULL;
opt.attr |= dropt_attr_hidden;
options.push_back(opt);
opt = emptyOpt;
opt.long_name = "version";
opt.description = "Shows version information.";
opt.handler = dropt::handle_bool;
opt.handler_data = &showVersion;
opt.attr = dropt_attr_halt;
options.push_back(opt);
opt = emptyOpt;
opt.short_name = 'i';
opt.long_name = "int";
opt.description = "Sample integer option.";
opt.arg_description = "value";
opt.handler = dropt::handle_int;
opt.handler_data = &i;
options.push_back(opt);
opt = emptyOpt;
opt.short_name = 'f';
opt.long_name = "face";
opt.description = "Sample custom option.";
opt.arg_description = "{heads, tails}";
opt.handler = handle_face;
opt.handler_data = &face;
options.push_back(opt);
// Required sentinel value.
options.push_back(emptyOpt);
dropt::context droptContext(&options[0]);
if (argc == 0)
{
/* This check is useless but is here for pedantic completeness.
* Hosted C environments are not required to supply command-line
* arguments, although obviously any environment that doesn't
* supply arguments wouldn't have any use for dropt.
*/
}
else
{
/* Parse the arguments from argv.
*
* argv[1] is always safe to access since argv[argc] is guaranteed
* to be NULL and since we've established that argc > 0.
*/
char** rest = droptContext.parse(-1, &argv[1]);
if (droptContext.get_error() != dropt_error_none)
{
std::cerr << "droptxx_example: " << droptContext.get_error_message() << std::endl;
return EXIT_FAILURE;
}
else if (showHelp)
{
std::cout << "Usage: droptxx_example [options] [--] [operands]\n\n"
<< "Options:\n"
<< droptContext.get_help()
<< std::endl;
}
else if (showVersion)
{
std::cout << "droptxx_example 1.0" << std::endl;
}
else
{
std::cout << "int value: " << i << "\n"
<< "face value: " << face << "\n"
<< "Operands: ";
while (*rest != NULL)
{
std::cout << *rest << " ";
rest++;
}
std::cout << std::endl;
}
}
return EXIT_SUCCESS;
}
/** handle_face
*
* An example of a custom option handler. Usually the stock callbacks
* (e.g. dropt_handle_bool, dropt_handle_int, dropt_handle_string,
* etc.) should be sufficient for most purposes.
*/
static dropt_error
handle_face(dropt_context* context, const char* optionArgument, void* handlerData)
{
dropt_error err = dropt_error_none;
face_type* face = static_cast(handlerData);
assert(face != NULL);
/* Option handlers should handle 'optionArgument' being NULL (if the
* option's argument is optional and wasn't supplied) or being the
* empty string (if a user explicitly passed an empty string (e.g.
* --face="").
*/
if (optionArgument == NULL || optionArgument[0] == '\0')
{
err = dropt_error_insufficient_arguments;
}
else if (strcmp(optionArgument, "heads") == 0)
{
*face = heads;
}
else if (strcmp(optionArgument, "tails") == 0)
{
*face = tails;
}
else
{
// Reject the value as being inappropriate for this handler.
err = dropt_error_mismatch;
}
return err;
}