man3/strcpy.3

   1 .\" Copyright (C) 1993 David Metcalfe (david@prism.demon.co.uk)
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  23 .\" References consulted:
  24 .\"     Linux libc source code
  25 .\"     Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991)
  26 .\"     386BSD man pages
  27 .\" Modified Sat Jul 24 18:06:49 1993 by Rik Faith (faith@cs.unc.edu)
  28 .\" Modified Fri Aug 25 23:17:51 1995 by Andries Brouwer (aeb@cwi.nl)
  29 .\" Modified Wed Dec 18 00:47:18 1996 by Andries Brouwer (aeb@cwi.nl)
  30 .\"
  31 .TH STRCPY 3  1993-04-11 "GNU" "Linux Programmer's Manual"
  32 .SH NAME
  33 strcpy, strncpy \- copy a string
  34 .SH SYNOPSIS
  35 .nf
  36 .B #include <string.h>
  37 .sp
  38 .BI "char *strcpy(char *" dest ", const char *" src );
  39 .sp
  40 .BI "char *strncpy(char *" dest ", const char *" src ", size_t " n );
  41 .fi
  42 .SH DESCRIPTION
  43 The \fBstrcpy()\fP function copies the string pointed to by \fIsrc\fP
  44 (including the terminating `\\0' character) to the array pointed to by
  45 \fIdest\fP.  The strings may not overlap, and the destination string
  46 \fIdest\fP must be large enough to receive the copy.
  47 .PP
  48 The \fBstrncpy()\fP function is similar, except that not more than
  49 \fIn\fP bytes of \fIsrc\fP are copied. Thus, if there is no null byte
  50 among the first \fIn\fP bytes of \fIsrc\fP, the result will not be
  51 null-terminated.
  52 .PP
  53 In the case where the length of
  54 .I src
  55 is less than that of
  56 .IR n ,
  57 the remainder of
  58 .I dest
  59 will be padded with nulls.
  60 .SH "RETURN VALUE"
  61 The \fBstrcpy()\fP and \fBstrncpy()\fP functions return a pointer to
  62 the destination string \fIdest\fP.
  63 .SH BUGS
  64 If the destination string of a \fBstrcpy()\fP is not large enough
  65 (that is, if the programmer was stupid/lazy, and failed to check
  66 the size before copying) then anything might happen.
  67 Overflowing fixed length strings is a favourite cracker technique.
  68 .SH "CONFORMING TO"
  69 SVID 3, POSIX, BSD 4.3, ISO 9899
  70 .SH "SEE ALSO"
  71 .BR bcopy (3),
  72 .BR memccpy (3),
  73 .BR memcpy (3),
  74 .BR memmove (3),
  75 .BR wcscpy (3),
  76 .BR wcsncpy (3)