STRDUP(3)                  POSIX Programmer's Manual                 STRDUP(3)



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

NNAAMMEE
       strdup, strndup -- duplicate a specific number of bytes from a string

SSYYNNOOPPSSIISS
       #include <string.h>

       char *strdup(const char *_s);
       char *strndup(const char *_s, size_t _s_i_z_e);

DDEESSCCRRIIPPTTIIOONN
       The _s_t_r_d_u_p() 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 _f_r_e_e().  A null pointer is returned if the new string cannot
       be created.

       The _s_t_r_n_d_u_p() function shall be equivalent to the _s_t_r_d_u_p() function,
       duplicating the provided _s in a new block of memory allocated as if by
       using _m_a_l_l_o_c(), with the exception being that _s_t_r_n_d_u_p() copies at most
       _s_i_z_e plus one bytes into the newly allocated memory, terminating the
       new string with a NUL character. If the length of _s is larger than
       _s_i_z_e, only _s_i_z_e bytes shall be duplicated. If _s_i_z_e 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.

RREETTUURRNN VVAALLUUEE
       The _s_t_r_d_u_p() function shall return a pointer to a new string on
       success. Otherwise, it shall return a null pointer and set _e_r_r_n_o to
       indicate the error.

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

EERRRROORRSS
       These functions shall fail if:

       EENNOOMMEEMM Storage space available is insufficient.

       _T_h_e _f_o_l_l_o_w_i_n_g _s_e_c_t_i_o_n_s _a_r_e _i_n_f_o_r_m_a_t_i_v_e_.

EEXXAAMMPPLLEESS
       None.

AAPPPPLLIICCAATTIIOONN UUSSAAGGEE
       For functions that allocate memory as if by _m_a_l_l_o_c(), the application
       should release such memory when it is no longer required by a call to
       _f_r_e_e().  For _s_t_r_d_u_p() and _s_t_r_n_d_u_p(), this is the return value.

       Implementations are free to _m_a_l_l_o_c() a buffer containing either (_s_i_z_e +
       1) bytes or (_s_t_r_n_l_e_n( _s, _s_i_z_e) + 1) bytes. Applications should not
       assume that _s_t_r_n_d_u_p() will allocate (_s_i_z_e + 1) bytes when _s_t_r_l_e_n( _s) is
       smaller than _s_i_z_e.

RRAATTIIOONNAALLEE
       None.

FFUUTTUURREE DDIIRREECCTTIIOONNSS
       None.

SSEEEE AALLSSOO
       _f_r_e_e(), _w_c_s_d_u_p()

       The Base Definitions volume of POSIX.1-2017, <<ssttrriinngg..hh>>

CCOOPPYYRRIIGGHHTT
       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 .



IEEE/The Open Group                  2017                            STRDUP(3)
