NAME

lsearch − linear search and update

SYNOPSIS

char ∗lsearch ((char ∗)key, (char ∗)base, nelp, width, compar)
unsigned ∗nelp, width;
int (∗compar)( );

DESCRIPTION

Lsearch is a linear search routine generalized from Knuth (6.1) Algorithm S.  It returns a pointer into a table indicating where a datum may be found.  If the datum does not occur, it is added at the end of the table.  Key points to the datum to be sought in the table.  Base points to the first element in the table.  Nelp points to an integer containing the current number of elements in the table.  The integer is incremented if the datum is added to the table.  Width is the width of an element in bytes; sizeof (*key) should be used.  Compar is the name of the comparison function which the user must supply (strcmp, for example). It is called with two arguments that point to the elements being compared. The function must return zero if the elements are equal and non-zero otherwise.

NOTES

The pointers to the key and the element at the base of the table should be of type pointer-to-element, and cast to type pointer-to-character. 
The comparison function need not compare every byte, so arbitrary data may be contained in the elements in addition to the values being compared.
Although declared as type pointer-to-character, the value returned should be cast into type pointer-to-element.

SEE ALSO

bsearch(3C), hsearch(3C), tsearch(3C)
The Art of Computer Programming, Volume 1, Sorting and Searching by Donald Knuth. 

BUGS

Undefined results can occur if there is not enough room in the table to add a new item. 

Version 2.3  —  July 04, 1985