HelenOS sources

IS_D_CHAR          42 uspace/app/mkfat/fat_dentry.h #define IS_D_CHAR(ch) (isalnum(ch) || ch == '_')
IS_D_CHAR          43 uspace/srv/fs/fat/fat_dentry.h #define IS_D_CHAR(ch) (isalnum(ch) || ch == '_')
HelenOS homepage, sources at GitHub