lfind, lsearch — linear search of an array


#include <search.h>
void *lfind( const void *key,
  const void *base,
  size_t *nmemb,
  size_t size,
  int(*compar)(const void *, const void *));
void *lsearch( const void *key,
  void *base,
  size_t *nmemb,
  size_t size,
  int(*compar)(const void *, const void *));


lfind() and lsearch() perform a linear search for key in the array base which has *nmemb elements of size bytes each. The comparison function referenced by compar is expected to have two arguments which point to the key object and to an array member, in that order, and which returns zero if the key object matches the array member, and nonzero otherwise.

If lsearch() does not find a matching element, then the key object is inserted at the end of the table, and *nmemb is incremented. In particular, one should know that a matching element exists, or that more room is available.


lfind() returns a pointer to a matching member of the array, or NULL if no match is found. lsearch() returns a pointer to a matching member of the array, or to the newly added member if no match is found.


For an explanation of the terms used in this section, see attributes(7).

Interface Attribute Value
lfind(), lsearch() Thread safety MT-Safe


POSIX.1-2001, POSIX.1-2008, SVr4, 4.3BSD. Present in libc since libc-4.6.27.


The naming is unfortunate.


bsearch(3), hsearch(3), tsearch(3)


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  Copyright 1995 Jim Van Zandt <>

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