RADIXSORT(3)

NAME
radixsort - radix sort

SYNOPSIS
#include <limits.h>
#include <stdlib.h>
int
radixsort(u_char **base, int nmemb, u_char *table, u_char endbyte);

DESCRIPTION
The radixsort() function is a modified radix sort.

The radixsort() function sorts an array of nmemb pointers to byte strings, the initial member of which is referenced by base. The byte strings may contain any values; the end of each string is denoted by the user-specified value endbyte. The contents of the array are sorted in ascending order according to the ASCII order of the byte strings they reference.

Applications may specify a sort order by providing the table argument. If non-NULL, table must reference an array of UCHAR_MAX + 1 bytes which contains the sort weight of each possible byte value. The end-of-string byte must have a sort weight of 0. More than one byte may have the same sort weight. The table argument is useful for applications which wish to sort different characters equally; for example, providing a table with the same weights for A-Z as for a-z will result in a case-insensitive sort.

The radixsort() function is stable, that is, if two elements compare as equal, their order in the sorted array is unchanged.

The radixsort() function is a variant of most-significant-byte radix sorting; in particular, see D.E. Knuth's Algorithm R and section 5.2.5, exercise 10. The radixsort() function takes linear time relative to the number of bytes in the strings.

RETURN VALUES
Upon successful completion 0 is returned. Otherwise, -1 is returned and the global variable errno is set to indicate the error.

ERRORS
The radixsort() function may fail and set errno for any of the errors specified for the library routine malloc(3).

SEE ALSO
sort(1), qsort(3)

Knuth, D.E., 1968, The Art of Computer Programming, Sorting and Searching, Vol. 3, pp. 170-178. Paige, R., 1987, Three Partition Refinement Algorithms, SIAM J. Comput., Vol. 16, No. 6.

HISTORY
The radixsort() function is

BUGS
The nmemb argument must be less than the maximum integer, INT_MAX.