man3/lsearch.3

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  24 .\" Corrected prototype and include, aeb, 990927
  25 .TH LSEARCH 3  1999-09-27 "GNU" "Linux Programmer's Manual"
  26 .SH NAME
  27 lfind, lsearch \- linear search of an array
  28 .SH SYNOPSIS
  29 .nf
  30 .B #include <search.h>
  31 .sp
  32 .BI "void *lfind(const void *" key ", const void *" base ", size_t *" nmemb ,
  33 .RS
  34 .BI "size_t " size ", int(*" compar ")(const void *, const void *));"
  35 .RE
  36 .sp
  37 .BI "void *lsearch(const void *" key ", void *" base ", size_t *" nmemb ,
  38 .RS
  39 .BI "size_t " size ", int(*" compar ")(const void *, const void *));"
  40 .RE
  41 .fi
  42 .SH DESCRIPTION
  43 \fBlfind\fP() and \fBlsearch\fP() perform a linear search for
  44 \fIkey\fP in the array \fIbase\fP which has *\fInmemb\fP elements of
  45 \fIsize\fP bytes each.  The comparison function referenced by
  46 \fIcompar\fP is expected to have two arguments which point to the
  47 \fIkey\fP object and to an array member, in that order, and which
  48 returns zero if the \fIkey\fP object matches the array member, and
  49 non-zero otherwise.
  50 .PP
  51 If \fBlsearch\fP() does not find a matching element, then the \fIkey\fP
  52 object is inserted at the end of the table, and *\fInmemb\fP is
  53 incremented.
  54 In particular, one should know that a matching element
  55 exists, or that more room is available.
  56 .SH "RETURN VALUE"
  57 \fBlfind\fP() returns a pointer to a matching member of the array, or
  58 \fBNULL\fP if no match is found.  \fBlsearch\fP() returns a pointer to
  59 a matching member of the array, or to the newly added member if no
  60 match is found.
  61 .SH "CONFORMING TO"
  62 SVID 1, SVID 3, 4.3BSD, POSIX 1003.1-2003.
  63 Present in libc since libc-4.6.27.
  64 .SH BUGS
  65 The naming is unfortunate.
  66 .SH "SEE ALSO"
  67 .BR bsearch (3),
  68 .BR hsearch (3),
  69 .BR tsearch (3)