ultrix man page for lsearch

lsearch(3)						     Library Functions Manual							lsearch(3)

Name
       lsearch, lfind - linear search and update

Syntax
       #include <search.h>
       #include <sys/types.h>

       void *lsearch (key, base, nelp, width, compar)
       void *key;
       void *base;
       size_t *nelp;
       size_t width;
       int (*compar)( );

       void *lfind (key, base, nelp, width, compar)
       void *key;
       void *base;
       size_t *nelp;
       size_t width;
       int (*compar)( );

Description
       The  subroutine	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.  The key points to the datum to be sought in the ta-
       ble.   The  base  points to the first element in the table.  The nelp points to an integer containing the current number of elements in the
       table.  The width is the size of an element in bytes.  The integer is incremented if the datum is added to the table.  The  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 ele-
       ments being compared.  The function must return zero if the elements are equal and non-zero otherwise.

       The subroutine is the same as lsearch except that if the datum is not found, it is not added to the table.   Instead,  a  NULL  pointer	is
       returned.  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.

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

Return Values
       If the searched for datum is found, both and return a pointer to it.  Otherwise, returns NULL and returns a pointer to the newly added ele-
       ment.

See Also
       bsearch(3), hsearch(3), tsearch(3)

																	lsearch(3)