man3/lsearch.3

.\" Copyright 1995 Jim Van Zandt <jrv@vanzandt.mv.com>
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.\" Corrected prototype and include, aeb, 990927
.TH LSEARCH 3  2017-09-15 "GNU" "Linux Programmer's Manual"
.SH NAME
lfind, lsearch \- linear search of an array
.SH SYNOPSIS
.nf
.B #include <search.h>
.PP
.BI "void *lfind(const void *" key ", const void *" base ", size_t *" nmemb ,
.BI "         size_t " size ", int(*" compar ")(const void *, const void *));"
.PP
.BI "void *lsearch(const void *" key ", void *" base ", size_t *" nmemb ,
.BI "         size_t " size ", int(*" compar ")(const void *, const void *));"
.fi
.SH DESCRIPTION
.BR lfind ()
and
.BR lsearch ()
perform a linear search for
.I key
in the array
.IR base
which has
.I *nmemb
elements of
.I size
bytes each.
The comparison function referenced by
.I compar
is expected to have two arguments which point to the
.I key
object and to an array member, in that order, and which
returns zero if the
.I key
object matches the array member, and
nonzero otherwise.
.PP
If
.BR lsearch ()
does not find a matching element, then the
.I key
object is inserted at the end of the table, and
.I *nmemb
is
incremented.
In particular, one should know that a matching element
exists, or that more room is available.
.SH RETURN VALUE
.BR lfind ()
returns a pointer to a matching member of the array, or
NULL if no match is found.
.BR lsearch ()
returns a pointer to
a matching member of the array, or to the newly added member if no
match is found.
.SH ATTRIBUTES
For an explanation of the terms used in this section, see
.BR attributes (7).
.TS
allbox;
lbw18 lb lb
l l l.
Interface	Attribute	Value
T{
.BR lfind (),
.BR lsearch ()
T}	Thread safety	MT-Safe
.TE
.sp 1
.SH CONFORMING TO
POSIX.1-2001, POSIX.1-2008, SVr4, 4.3BSD.
Present in libc since libc-4.6.27.
.SH BUGS
The naming is unfortunate.
.SH SEE ALSO
.BR bsearch (3),
.BR hsearch (3),
.BR tsearch (3)