SCANDIR(3)

NAME
scandir, alphasort - scan a directory for matching entries

SYNOPSIS
#include <dirent.h>

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

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

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

The alphasort() function can be used as the comparison function for the scandir() function to sort the directory entries into alphabetical order. Its parameters are the two directory entries, a and b, to compare.

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

The alphasort() function returns an integer less than, equal to, or greater than zero if the first argument is considered to be respectively less than, equal to, or greater than the second.

ERRORS

ENOMEM
    Insufficient memory to complete the operation.

CONFORMING TO
BSD 4.3

EXAMPLE
/* print files in current directory in reverse order */
#include <dirent.h>
main(){
    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);
}

SEE ALSO
opendir(3), readdir(3), closedir(3), rewinddir(3), telldir(3), seekdir(3).