POSIX_SPAWN_FILE_ACTIONS_ADDPDOUSPI2X(3P)rogrammer'PsOSMIaXn_uSaPlAWN_FILE_ACTIONS_ADDDUP2(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
       posix_spawn_file_actions_adddup2 -- add dup2 action to spawn file
       actions object (AADDVVAANNCCEEDD RREEAALLTTIIMMEE)

SSYYNNOOPPSSIISS
       #include <spawn.h>

       int posix_spawn_file_actions_adddup2(posix_spawn_file_actions_t
           *_f_i_l_e___a_c_t_i_o_n_s, int _f_i_l_d_e_s, int _n_e_w_f_i_l_d_e_s);

DDEESSCCRRIIPPTTIIOONN
       The _p_o_s_i_x___s_p_a_w_n___f_i_l_e___a_c_t_i_o_n_s___a_d_d_d_u_p_2() function shall add a _d_u_p_2()
       action to the object referenced by _f_i_l_e___a_c_t_i_o_n_s that shall cause the
       file descriptor _f_i_l_d_e_s to be duplicated as _n_e_w_f_i_l_d_e_s (as if
       _d_u_p_2(_f_i_l_d_e_s, _n_e_w_f_i_l_d_e_s) had been called) when a new process is spawned
       using this file actions object.

       A spawn file actions object is as defined in
       _p_o_s_i_x___s_p_a_w_n___f_i_l_e___a_c_t_i_o_n_s___a_d_d_c_l_o_s_e().

RREETTUURRNN VVAALLUUEE
       Upon successful completion, the _p_o_s_i_x___s_p_a_w_n___f_i_l_e___a_c_t_i_o_n_s___a_d_d_d_u_p_2()
       function shall return zero; otherwise, an error number shall be
       returned to indicate the error.

EERRRROORRSS
       The _p_o_s_i_x___s_p_a_w_n___f_i_l_e___a_c_t_i_o_n_s___a_d_d_d_u_p_2() function shall fail if:

       EEBBAADDFF  The value specified by _f_i_l_d_e_s or _n_e_w_f_i_l_d_e_s is negative or
              greater than or equal to {OPEN_MAX}.

       EENNOOMMEEMM Insufficient memory exists to add to the spawn file actions
              object.

       The _p_o_s_i_x___s_p_a_w_n___f_i_l_e___a_c_t_i_o_n_s___a_d_d_d_u_p_2() function may fail if:

       EEIINNVVAALL The value specified by _f_i_l_e___a_c_t_i_o_n_s is invalid.

       It shall not be considered an error for the _f_i_l_d_e_s argument passed to
       the _p_o_s_i_x___s_p_a_w_n___f_i_l_e___a_c_t_i_o_n_s___a_d_d_d_u_p_2() function to specify a file
       descriptor for which the specified operation could not be performed at
       the time of the call. Any such error will be detected when the
       associated file actions object is later used during a _p_o_s_i_x___s_p_a_w_n() or
       _p_o_s_i_x___s_p_a_w_n_p() operation.

       _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
       The _p_o_s_i_x___s_p_a_w_n___f_i_l_e___a_c_t_i_o_n_s___a_d_d_d_u_p_2() function is part of the Spawn
       option and need not be provided on all implementations.

       Implementations may use file descriptors that must be inherited into
       child processes for the child process to remain conforming, such as for
       message catalog or tracing purposes. Therefore, an application that
       calls _p_o_s_i_x___s_p_a_w_n___f_i_l_e___a_c_t_i_o_n_s___a_d_d_d_u_p_2() with an arbitrary integer for
       _n_e_w_f_i_l_d_e_s risks non-conforming behavior, and this function can only
       portably be used to overwrite file descriptor values that the
       application has obtained through explicit actions, or for the three
       file descriptors corresponding to the standard file streams. In order
       to avoid a race condition of leaking an unintended file descriptor into
       a child process, an application should consider opening all file
       descriptors with the FD_CLOEXEC bit set unless the file descriptor is
       intended to be inherited across _e_x_e_c.

RRAATTIIOONNAALLEE
       Refer to the RATIONALE section in _p_o_s_i_x___s_p_a_w_n___f_i_l_e___a_c_t_i_o_n_s___a_d_d_c_l_o_s_e().

FFUUTTUURREE DDIIRREECCTTIIOONNSS
       None.

SSEEEE AALLSSOO
       _d_u_p(), _p_o_s_i_x___s_p_a_w_n(), _p_o_s_i_x___s_p_a_w_n___f_i_l_e___a_c_t_i_o_n_s___a_d_d_c_l_o_s_e(),
       _p_o_s_i_x___s_p_a_w_n___f_i_l_e___a_c_t_i_o_n_s___d_e_s_t_r_o_y()

       The Base Definitions volume of POSIX.1-2017, <<ssppaawwnn..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  POSIX_SPAWN_FILE_ACTIONS_ADDDUP2(3)
