--- lsx.c.bak	2006-10-12 17:12:51.000000000 +0200
+++ lsx.c	2006-10-12 17:39:12.000000000 +0200
@@ -8,6 +8,16 @@
 #include <sys/stat.h>
 #include <sys/types.h>
 #include <stdlib.h>
+#include <string.h>
+
+int
+ingroups(struct stat* s, int size, gid_t list[]) {
+	int i;
+	for(i = 0; i < size; i++)
+		if(s->st_gid == list[i])
+			return 1;
+	return 0;
+}
 
 int
 main(int argc, char *argv[]) {
@@ -17,6 +27,10 @@
 	struct stat s;
 	uid_t uid = getuid();
 	DIR *dir;
+	long ngroups_max;
+	ngroups_max = sysconf(_SC_NGROUPS_MAX);
+	gid_t gid_l[ngroups_max];
+	int ngroups = getgroups(ngroups_max, gid_l);
 
 	if((argc > 1) && !strncmp(argv[1], "-v", 3)) {
 		fputs("lsx-"VERSION", (C)opyright MMVI Anselm R. Garbe\n", stdout);
@@ -30,7 +44,7 @@
 					&& (stat(dp->d_name, &s) != -1)
 					&& S_ISREG (s.st_mode)
 					&& ((s.st_uid == uid && s.st_mode & S_IXUSR) ||
-						(s.st_gid == gid && s.st_mode & S_IXGRP) ||
+						((s.st_gid == gid || ingroups(&s, ngroups, gid_l)) &&s.st_mode & S_IXGRP) ||
 						(s.st_mode & S_IXOTH)))
 					puts(dp->d_name);
 			while(dp);