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 .BI "         size_t " size ", int(*" compar ")(const void *, const void *));"
  34 .sp
  35 .BI "void *lsearch(const void *" key ", void *" base ", size_t *" nmemb ,
  36 .BI "         size_t " size ", int(*" compar ")(const void *, const void *));"
  37 .fi
  38 .SH DESCRIPTION
  39 .BR lfind ()
  40 and
  41 .BR lsearch ()
  42 perform a linear search for
  43 \fIkey\fP in the array \fIbase\fP which has \fI*nmemb\fP elements of
  44 \fIsize\fP bytes each.
  45 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
  52 .BR lsearch ()
  53 does not find a matching element, then the \fIkey\fP
  54 object is inserted at the end of the table, and \fI*nmemb\fP is
  55 incremented.
  56 In particular, one should know that a matching element
  57 exists, or that more room is available.
  58 .SH "RETURN VALUE"
  59 .BR lfind ()
  60 returns a pointer to a matching member of the array, or
  61 NULL if no match is found.
  62 .BR lsearch ()
  63 returns a pointer to
  64 a matching member of the array, or to the newly added member if no
  65 match is found.
  66 .SH "CONFORMING TO"
  67 SVr4, 4.3BSD, POSIX.1-2001.
  68 Present in libc since libc-4.6.27.
  69 .SH BUGS
  70 The naming is unfortunate.
  71 .SH "SEE ALSO"
  72 .BR bsearch (3),
  73 .BR hsearch (3),
  74 .BR tsearch (3)