man3/lsearch.3

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.TH LSEARCH 3  1999-09-27 "GNU" "Linux Programmer's Manual"
.SH NAME
lfind, lsearch \- linear search of an array
.SH SYNOPSIS
.nf
.B #include <search.h>
.sp
.BI "void *lfind(const void *" key ", const void *" base ", size_t *" nmemb ,
.BI "         size_t " size ", int(*" compar ")(const void *, const void *));"
.sp
.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
\fIkey\fP in the array \fIbase\fP which has \fI*nmemb\fP elements of
\fIsize\fP bytes each.
The comparison function referenced by
\fIcompar\fP is expected to have two arguments which point to the
\fIkey\fP object and to an array member, in that order, and which
returns zero if the \fIkey\fP object matches the array member, and
nonzero otherwise.
.PP
If
.BR lsearch ()
does not find a matching element, then the \fIkey\fP
object is inserted at the end of the table, and \fI*nmemb\fP 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 "CONFORMING TO"
SVr4, 4.3BSD, POSIX.1-2001.
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)