scandir(3) - NetBSD Manual Pages

SCANDIR(3)              NetBSD Library Functions Manual             SCANDIR(3)


NAME

     scandir, alphasort -- scan a directory


LIBRARY

     Standard C Library (libc, -lc)


SYNOPSIS

     #include <sys/types.h>
     #include <dirent.h>

     int
     scandir(const char *dirname, struct dirent ***namelist,
         int (*select)(const struct dirent *),
         int (*compar)(const struct dirent **, const struct dirent **));

     int
     alphasort(const struct dirent **d1, const struct dirent **d2);


DESCRIPTION

     The scandir() function reads the directory dirname and builds an array of
     pointers to directory entries using malloc(3).  It returns the number of
     entries in the array.  A pointer to the array of directory entries is
     stored in the location referenced by namelist.

     The select parameter is a pointer to a user supplied subroutine which is
     called by scandir() to select which entries are to be included in the
     array.  The select routine is passed a pointer to a directory entry and
     should return a non-zero value if the directory entry is to be included
     in the array.  If select is null, then all the directory entries will be
     included.

     The compar parameter is a pointer to a user supplied subroutine which is
     passed to qsort(3) to sort the completed array.  If this pointer is null,
     the array is not sorted.

     The alphasort() function is a routine which can be used for the compar
     parameter to sort the array alphabetically.

     The memory allocated for the array can be deallocated with free(3), by
     freeing each pointer in the array and then the array itself.


RETURN VALUES

     Returns -1 if the directory cannot be opened for reading or if malloc(3)
     cannot allocate enough memory to hold all the data structures.


SEE ALSO

     directory(3), dirent(3), malloc(3), qsort(3)


STANDARDS

     The scandir() and alphasort() functions conform to IEEE Std 1003.1-2008
     (``POSIX.1'').


HISTORY

     The scandir() and alphasort() functions appeared in 4.2BSD.

     They were changed in NetBSD 8.0 to use ``struct dirent **'' instead of
     ``void *'' for the comparison function, including alphasort().

NetBSD 10.99                   December 15, 2016                  NetBSD 10.99