scandir

Name

scandir, alphasort
- scan a directory

Library

libc.lib

Synopsis

#include <sys/types.h>

#include <dirent.h>

int scandir (const char *dirname, struct dirent ***namelist, int \*(lp*select\*(rp\*(lpstruct dirent *\*(rp, int \*(lp*compar\*(rp\*(lpconst void *, const void *\*(rp);

int alphasort (const void *d1, const void *d2);

Detailed description

The scandir function reads the directory dirname and builds an array of pointers to directory entries using malloc 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 argument 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 argument is a pointer to a user supplied subroutine which is passed to qsort 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 argument to sort the array alphabetically.

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

Examples

//Illustrates how to use scandir API.
#include <dirent.h>
Void  scandirTest()
    {
       struct dirent **namelist;
       int n;
       // Function call to get the dir entries into the namelist.
       n = scandir("\home\manjus\GETTEXT", &namelist, 0, 0);
      
       if(n > 0) // if scandir is successful it retuns the number of entries greater than 0
       {
             // print all the entries in the directory.
        while(n--)
        {
                printf("dir name @ pos %d is %s \n",n,namelist[n]->d_name);
        }
       }
     }

Diagnostics

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