4.3BSD-UWisc/man/cat3/directory.3

DIRECTORY(3)        UNIX Programmer's Manual         DIRECTORY(3)



NAME
     opendir, readdir, telldir, seekdir, rewinddir, closedir -
     directory operations

SYNOPSIS
     #include <sys/types.h>
     #include <sys/dir.h>

     DIR *opendir(filename)
     char *filename;

     struct direct *readdir(dirp)
     DIR *dirp;

     long telldir(dirp)
     DIR *dirp;

     seekdir(dirp, loc)
     DIR *dirp;
     long loc;

     rewinddir(dirp)
     DIR *dirp;

     closedir(dirp)
     DIR *dirp;

DESCRIPTION
     _O_p_e_n_d_i_r opens the directory named by _f_i_l_e_n_a_m_e and associates
     a _d_i_r_e_c_t_o_r_y _s_t_r_e_a_m with it.  _O_p_e_n_d_i_r returns a pointer to be
     used to identify the _d_i_r_e_c_t_o_r_y _s_t_r_e_a_m in subsequent opera-
     tions.  The pointer NULL is returned if _f_i_l_e_n_a_m_e cannot be
     accessed, or if it cannot _m_a_l_l_o_c(3) enough memory to hold
     the whole thing.

     _R_e_a_d_d_i_r returns a pointer to the next directory entry.  It
     returns NULL upon reaching the end of the directory or
     detecting an invalid _s_e_e_k_d_i_r operation.

     _T_e_l_l_d_i_r returns the current location associated with the
     named _d_i_r_e_c_t_o_r_y _s_t_r_e_a_m.

     _S_e_e_k_d_i_r sets the position of the next _r_e_a_d_d_i_r operation on
     the _d_i_r_e_c_t_o_r_y _s_t_r_e_a_m. The new position reverts to the one
     associated with the _d_i_r_e_c_t_o_r_y _s_t_r_e_a_m when the _t_e_l_l_d_i_r opera-
     tion was performed.  Values returned by _t_e_l_l_d_i_r are good
     only for the lifetime of the DIR pointer from which they are
     derived.  If the directory is closed and then reopened, the
     _t_e_l_l_d_i_r value may be invalidated due to undetected directory
     compaction.  It is safe to use a previous _t_e_l_l_d_i_r value
     immediately after a call to _o_p_e_n_d_i_r and before any calls to
     _r_e_a_d_d_i_r.



Printed 12/27/86       September 24, 1985                       1






DIRECTORY(3)        UNIX Programmer's Manual         DIRECTORY(3)



     _R_e_w_i_n_d_d_i_r resets the position of the named _d_i_r_e_c_t_o_r_y _s_t_r_e_a_m
     to the beginning of the directory.

     _C_l_o_s_e_d_i_r closes the named _d_i_r_e_c_t_o_r_y _s_t_r_e_a_m and frees the
     structure associated with the DIR pointer.

     Sample code which searchs a directory for entry ``name'' is:

          len = strlen(name);
          dirp = opendir(".");
          for (dp = readdir(dirp); dp != NULL; dp =
     readdir(dirp))
               if (dp->d_namlen == len && !strcmp(dp->d_name,
     name)) {
                    closedir(dirp);
                    return FOUND;
               }
          closedir(dirp);
          return NOT_FOUND;

SEE ALSO
     open(2), close(2), read(2), lseek(2), dir(5)

































Printed 12/27/86       September 24, 1985                       2