Xinu7/man/man3/ckmode.doc

CKMODE(3)           Xinu Programmer's Manual            CKMODE(3)



NAME
     ckmode - check a file mode string and convert to integer
     representation

SYNOPSIS
     #include <file.h>

     int chmode(mode)
     char *mode;

DESCRIPTION
     _C_k_m_o_d_e parses a null-terminated string, _m_o_d_e, containing
     characters that represent file modes, and produces an
     integer with mode bits set.  The possible mode characters
     are:

     r    The file is to be opened for reading (i.e., input).

     w    The file is to be opened for writing (i.e., output).

     n    The file must be new.  That is, it must not already
          exist.

     o    The file must be old.  That is, it must already exist.

     The file mode string, _m_o_d_e, can specify that the file is to
     be accessed for both reading and writing, but it cannot
     specify the mode to be both old and new.  If neither reading
     nor writing is specified, _c_k_m_o_d_e assumes the file will be
     used for both.  Similarly, if neither old or new files are
     specified, _c_k_m_o_d_e assumes either is allowed.

     Given a legal mode string, _c_k_m_o_d_e returns an integer with
     bits _F_L_R_E_A_D, FLWRITE, FLOLD, and FLNEW set according to the
     argument, _m_o_d_e.  _C_k_m_o_d_e returns SYSERR if it finds illegal
     or duplicated characters in the argument string, or if the
     mode string specifies that the file must be both old and
     new.

















Version 6b               Printed 1/12/87                        1