plucky (3) strdup.3posix.gz

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PROLOG
       This  manual  page  is part of the POSIX Programmer's Manual.  The Linux implementation of this interface
       may differ (consult the corresponding Linux manual page for details of Linux behavior), or the  interface
       may not be implemented on Linux.


NAME
       strdup, strndup — duplicate a specific number of bytes from a string


SYNOPSIS
       #include <string.h>

       char *strdup(const char *s);
       char *strndup(const char *s, size_t size);


DESCRIPTION
       The  strdup() function shall return a pointer to a new string, which is a duplicate of the string pointed
       to by s.  The returned pointer can be passed to free().  A null pointer is returned  if  the  new  string
       cannot be created.

       The  strndup() function shall be equivalent to the strdup() function, duplicating the provided s in a new
       block of memory allocated as if by using malloc(), with the exception being that strndup() copies at most
       size  plus one bytes into the newly allocated memory, terminating the new string with a NUL character. If
       the length of s is larger than size, only size bytes shall be duplicated. If  size  is  larger  than  the
       length  of  s,  all  bytes in s shall be copied into the new memory buffer, including the terminating NUL
       character. The newly created string shall always be properly terminated.


RETURN VALUE
       The strdup() function shall return a pointer to a new string on success. Otherwise,  it  shall  return  a
       null pointer and set errno to indicate the error.

       Upon  successful  completion, the strndup() function shall return a pointer to the newly allocated memory
       containing the duplicated string. Otherwise, it shall return a null pointer and set errno to indicate the
       error.


ERRORS
       These functions shall fail if:

       ENOMEM Storage space available is insufficient.

       The following sections are informative.


EXAMPLES
       None.


APPLICATION USAGE
       For  functions that allocate memory as if by malloc(), the application should release such memory when it
       is no longer required by a call to free().  For strdup() and strndup(), this is the return value.

       Implementations are free to malloc() a buffer containing either (size + 1) bytes or (strnlen( s, size)  +
       1) bytes. Applications should not assume that strndup() will allocate (size + 1) bytes when strlen( s) is
       smaller than size.


RATIONALE
       None.


FUTURE DIRECTIONS
       None.


SEE ALSO
       free(), wcsdup()

       The Base Definitions volume of POSIX.1‐2017, <string.h>


       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1-2017, Standard
       for  Information  Technology  --  Portable  Operating  System  Interface  (POSIX),  The  Open  Group Base
       Specifications Issue 7, 2018 Edition, Copyright (C) 2018 by the Institute of Electrical  and  Electronics
       Engineers, Inc and The Open Group.  In the event of any discrepancy between this version and the original
       IEEE and The Open Group Standard, the original IEEE and The Open Group Standard is the referee  document.
       The original Standard can be obtained online at http://www.opengroup.org/unix/online.html .

       Any  typographical  or formatting errors that appear in this page are most likely to have been introduced
       during  the  conversion  of  the  source  files  to  man  page  format.  To  report  such   errors,   see
       https://www.kernel.org/doc/man-pages/reporting_bugs.html .