#include <stdio.h>
#include <stdlib.h>
#include <glib.h>
	
gchar * 
find_decimal_dot_double_decimal (const gchar *string)
{
	GRegex *regex = NULL;
	GMatchInfo *match_info;
	GString *lilyversion = g_string_new ("");

	regex = g_regex_new("\\d.\\d\\d", 0, 0, NULL);
	g_regex_match(regex, string, 0, &match_info);

	if (g_match_info_matches (match_info))
        {
	  g_string_append(lilyversion, g_match_info_fetch (match_info, 0));
	}
	  
	g_match_info_free (match_info);
	g_regex_unref (regex);
	return g_string_free(lilyversion, FALSE); 	  
}

double
get_lily_version (void)
{
	GError *error = NULL;
	gchar *endp, *version_string;
	double d;
	int standard_output;
	gchar buf[30];

	gchar *arguments[] = {
	  "lilypond",
	  "-v",
	  NULL
	};

	g_spawn_async_with_pipes (NULL,            /* dir */
	  arguments, NULL,       /* env */
	  G_SPAWN_SEARCH_PATH | G_SPAWN_DO_NOT_REAP_CHILD, NULL, /* child setup func */
	  NULL,          /* user data */
	  NULL,	/*pid*/
	  NULL, 	/*standard_input*/
	  &standard_output,	/*standard output*/
	  NULL,	/*standard error*/
	  &error);

	read(standard_output, buf, 30);
	version_string = find_decimal_dot_double_decimal(buf);
	if (!version_string) 
	  return -1;
	d = strtod(version_string, &endp);
	if (version_string != endp && *endp == '\0')
   	  return d;
	else 
	  return -1;
}


int 
main()
{
	double version;
	version = get_lily_version();
	if (version != -1)
   	  g_print("\nlilypond version = %g\n",version);
	else 
	  g_print("\nerror finding lilypond version\n");

}