Man Alphasort en anglais
SCANDIR(3)                 Linux Programmer's Manual                SCANDIR(3)



 

NAME


       scandir, alphasort, versionsort - scan a directory for matching entries

 

SYNOPSIS


       #include 

       int scandir(const char *dir, struct dirent ***namelist,
              int (*filter)(const struct dirent *),
              int (*compar)(const struct dirent **, const struct dirent **));

       int alphasort(const void *a, const void *b);

       int versionsort(const void *a, const void *b);

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       scandir(), alphasort(): _BSD_SOURCE || _SVID_SOURCE
       versionsort(): _GNU_SOURCE

 

DESCRIPTION






       The scandir() function scans the directory  dir,  calling  filter()  on
       each  directory entry.  Entries for which filter() returns non-zero are
       stored in strings allocated via malloc(3), sorted using  qsort(3)  with
       the comparison function compar(), and collected in array namelist which
       is allocated via  malloc(3).   If  filter  is  NULL,  all  entries  are
       selected.

       The alphasort() and versionsort() functions can be used as the compari-
       son function compar().  The former sorts directory entries  using  str-
       coll(3), the latter using strverscmp(3) on the strings (*a)->d_name and
       (*b)->d_name.

 

RETURN VALUE


       The scandir() function returns the number of directory entries selected
       or -1 if an error occurs.

       The  alphasort()  and  versionsort()  functions  return an integer less
       than, equal to, or greater than zero if the first argument  is  consid-
       ered  to  be respectively less than, equal to, or greater than the sec-
       ond.

 

ERRORS


       ENOMEM Insufficient memory to complete the operation.

 

CONFORMING TO


       None of these functions is in POSIX.1-2001, but alphasort()  and  scan-
       dir() are under consideration for a future revision to POSIX.1.

       The  functions scandir() and alphasort() are from 4.3BSD, and have been
       available under Linux since libc4.  Libc4 and libc5 use the  more  pre-
       cise prototype

           int alphasort(const struct dirent ** a,
                         const struct dirent **b);

       but glibc 2.0 returns to the imprecise BSD prototype.

       The  function  versionsort()  is a GNU extension, available since glibc
       2.1.

       Since glibc 2.1, alphasort() calls strcoll(3);  earlier  it  used  str-
       cmp(3).

 

EXAMPLE


       #define _SVID_SOURCE
       /* print files in current directory in reverse order */
       #include 

       int
       main(void)
       {
           struct dirent **namelist;
           int n;

           n = scandir(".", &namelist, 0, alphasort);
           if (n < 0)
               perror("scandir");
           else {
               while (n--) {
                   printf("%s\n", namelist[n]->d_name);
                   free(namelist[n]);
               }
               free(namelist);
           }
       }

 

SEE ALSO


       closedir(3),    fnmatch(3),   opendir(3),   readdir(3),   rewinddir(3),
       seekdir(3), strcmp(3), strcoll(3), strverscmp(3), telldir(3)

 

COLOPHON


       This page is part of release 3.05 of the Linux  man-pages  project.   A
       description  of  the project, and information about reporting bugs, can
       be found at http://www.kernel.org/doc/man-pages/.



GNU                               2007-07-26                        SCANDIR(3)