The scandir( ) function shall scan the directory dir, calling the function referenced by sel on each directory entry. Entries for which the function referenced by sel returns non-zero shall be stored in strings allocated as if by a call to malloc( ), and sorted as if by a call to qsort( ) with the comparison function compar, except that compar need not provide total ordering. The strings are collected in array namelist which shall be allocated as if by a call to malloc( ). If sel is a null pointer, all entries shall be selected. If the comparison function compar does not provide total ordering, the order in which the directory entries are stored is unspecified.

The scandir( ) function shall scan the directory dir, calling the function referenced by sel on each directory entry. Entries for which the function referenced by sel returns non-zero shall be stored in dirent structures allocated as if by a call to malloc( ), and sorted as if by a call to qsort( ) with the comparison function compar, except that compar need not provide total ordering. The dirent structures are collected in the array pointed to by namelist which shall be allocated as if by a call to malloc( ) if at least one entry is selected by sel; if no entries are selected, it is unspecified whether the array is allocated as if by a call to malloc or the value pointed to by namelist is set to a null pointer. If sel is a null pointer, all entries shall be selected. If the comparison function compar does not provide total ordering, the order in which the directory entries are stored is unspecified.

#include <dirent.h>
#include <stdio.h>
#include <stdlib.h>
...
struct dirent **files;
int i,n;

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

For functions that allocate memory as if by malloc( ), the application should release such memory when it is no longer required by a call to free( ). For scandir( ), this is namelist (including all of the individual strings in namelist).

For functions that allocate memory as if by malloc( ), the application should deallocate such memory when it is no longer required by a call to free( ). For scandir( ), this is the array pointed to by namelist (including all of the individual dirent structures in the array).