SCANDIR(3) Library Routines SCANDIR(3)
scandir, alphasort - scan a directory
int scandir (const char *dirname, struct dirent ***namelist, int
(*select) (struct dirent *), int (*compar) (const void *, const void
int alphasort (const void *d1, const void *d2);
int alphacasesort (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
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 alphacasesort function is similar to alphasort, but can be used for
sorting in a case-insensitive manner, and is useful for the case-insen-
sitive filesystems used by GNO. This function is specific to GNO.
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 mal-
loc(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.
GNO 27 January 1997 SCANDIR(3)
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