scandir, alphasort - scan a directory
Standard C Library (libc, -lc)
scandir(const char *dirname, struct dirent ***namelist,
int (*select)(const struct dirent *),
int (*compar)(const void *, const void *));
alphasort(const void *d1, const void *d2);
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
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.
Returns -1 if the directory cannot be opened for reading or if malloc(3)
cannot allocate enough memory to hold all the data structures.
directory(3), malloc(3), qsort(3), dir(5)
The scandir() and alphasort() functions appeared in 4.2BSD.
BSD June 4, 1993 BSD
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