scandir.doc

汇编大全 中国矿业大学计算机学院 汇编实验5

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     NNNAAAMMMEEE
          scandir, alphasort - scan a directory

     SSSYYYNNNOOOPPPSSSIIISSS
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          ####iiiinnnncccclllluuuuddddeeee <<<<ssssyyyyssss////ddddiiiirrrreeeennnntttt....hhhh>>>>

          iiiinnnntttt
          ssssccccaaaannnnddddiiiirrrr((((nnnnaaaammmmeeee,,,, lllliiiisssstttt,,,, sssseeeelllleeeeccccttttoooorrrr,,,, ssssoooorrrrtttteeeerrrr))))
              cccchhhhaaaarrrr ****nnnnaaaammmmeeee;;;;
              ssssttttrrrruuuucccctttt ddddiiiirrrreeeennnntttt ************lllliiiisssstttt;;;;
              iiiinnnntttt ((((****sssseeeelllleeeeccccttttoooorrrr))))(((())));;;;
              iiiinnnntttt ((((****ssssoooorrrrtttteeeerrrr))))(((())));;;;

          iiiinnnntttt
          aaaallllpppphhhhaaaassssoooorrrrtttt((((dddd1111,,,, dddd2222))))
              ssssttttrrrruuuucccctttt ddddiiiirrrreeeennnntttt ********dddd1111;;;;
              ssssttttrrrruuuucccctttt ddddiiiirrrreeeennnntttt ********dddd2222;;;;

     DDDEEESSSCCCRRRIIIPPPTTTIIIOOONNN
          _S_c_a_n_d_i_r reads the directory _n_a_m_e and builds a
          NULL-terminated array of pointers to the entries found in
          that directory.  This array is put into the location pointed
          to by the _l_i_s_t parameter.

          If the _s_e_l_e_c_t_o_r parameter is non-NULL, it is taken to be a
          pointer to a function called with each entry, to determine
          whether or not it should be included in the returned list.
          If the parameter is NULL, all entries are included.

          As an added feature, the entries can be sorted (with
          _q_s_o_r_t(3)) before the list is returned.  If the _s_o_r_t_e_r
          parameter is non-NULL, it is passed to qsort to use as the
          comparison function.  The _a_l_p_h_a_s_o_r_t routine is provided to
          sort the array alphabetically.

          The array pointed to by _l_i_s_t and the items it points to are
          all space obtained through _m_a_l_l_o_c(3), and their storage can
          be reclaimed as shown in the example below.

     EEEXXXAAAMMMPPPLLLEEE














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          Here is a small _l_s(1)-like program:
               #include <stdio.h>
               #include <sys/types.h>
               #include <sys/stat.h>
               #include <sys/dir.h>

               extern int alphasort();

               static int
               filesonly(e)
                    struct dirent *e;
               {
                    struct stat sb;

                    return(stat(e->d_name, &sb) >= 0 && (sb.st_mode & S_IFMT) == S_IFREG);
               }

               main(ac, av)
                    int ac;
                    char *av[];
               {
                    register int i;
                    register int j;
                    struct dirent **list;

                    if (ac != 2) {
                         fprintf(stderr, "usage: %s dirname0, av[0]);
                         exit(1);
                    }
                    if (chdir(av[1]) < 0) {
                         perror(av[1]);
                         exit(1);
                    }
                    if ((i = scandir(".", &list, filesonly, alphasort)) < 0) {
                         perror("Error reading directory");
                         exit(1);
                    }
                    for (j = 0; j < i; j++)
                         printf("%s0, list[j]->d_name);
                    for (j = 0; j < i; j++)
                         free((char *)list[j]);
                    free((char *)list);
                    exit(0);
               }

     SSSEEEEEE AAALLLSSSOOO
          directory(3), qsort(3)

     DDDIIIAAAGGGNNNOOOSSSTTTIIICCCSSS
          Returns the number of entries in the ``list,'' or -1 if the
          directory could not be opened or a memory allocation failed.




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     BBBUUUGGGSSS
          The routine can be slightly wasteful of space.





















































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