modecanon(3)

NAME

       modecanon - canonical file mode representation

SYNOPSIS

       #include <modex.h>

       int    modei(int external); int    modex(int internal);

DESCRIPTION

       POSIX  threw  out the file type bit macros and replaced them with func-
       tion-like macros that test file type.  This is bad in  many  ways,  the
       worst of which is that it provides no way for a user program to synthe-
       size file types in the mode bits.  pax(1), tar(1) and cpio(1) are exam-
       ples  of user programs that must convert between the internal mode rep-
       resentation and a private external representation.  These routines pro-
       vide a canonical external representation with macros to access and syn-
       thesize the bits in the external representation.

       modei takes an external mode representation external  and  returns  the
       equivalent internal representation.

       modex  takes  an  internal mode representation internal and returns the
       equivalent external representation.

       The traditional bit access macro (S_ prefix changes to X_) are: X_IFMT,
       X_IFSOCK,   X_IFLNK,   X_IFCTG,  X_IFREG,  X_IFBLK,  X_IFDIR,  X_IFCHR,
       X_IFIFO, X_IPERM, X_ISUID, X_ISGID, X_ISVTX, X_IRUSR, X_IWUSR, X_IXUSR,
       X_IRGRP,  X_IWGRP, X_IXGRP, X_IROTH, X_IWOTH, X_IXOTH, X_IRWXU, X_IRWXG
       and X_IRWXO.  returns the type bits for mode.

SEE ALSO

       pax(1), stat(2)

                                                                  MODECANON(3)