explain_dup2_or_die(3) [debian man page]

explain_dup2_or_die(3)					     Library Functions Manual					    explain_dup2_or_die(3)

NAME

       explain_dup2_or_die - duplicate a file descriptor and report errors

SYNOPSIS

       #include <libexplain/dup2.h>
       void explain_dup2_or_die(int oldfd, int newfd);

DESCRIPTION

       The  explain_dup2_or_die  function  is used to call the dup2(2) system call.  On failure an explanation will be printed to stderr, obtained
       from explain_dup2(3), and then the process terminates by calling exit(EXIT_FAILURE).

       This function is intended to be used in a fashion similar to the following example:
	      explain_dup2_or_die(oldfd, newfd);

       oldfd   The oldfd, exactly as to be passed to the dup2(2) system call.

       newfd   The newfd, exactly as to be passed to the dup2(2) system call.

       Returns:
	       This function only returns on success.  On failure, prints an explanation and exits.

SEE ALSO

       dup2(2) duplicate a file descriptor

       explain_dup2(3)
	       explain dup2(2) errors

       exit(2) terminate the calling process

COPYRIGHT

       libexplain version 0.52
       Copyright (C) 2008 Peter Miller

															    explain_dup2_or_die(3)

DUP(2)							     Linux Programmer's Manual							    DUP(2)

NAME

       dup, dup2 - duplicate a file descriptor

SYNOPSIS

       #include <unistd.h>

       int dup(int oldfd);
       int dup2(int oldfd, int newfd);

DESCRIPTION

       dup and dup2 create a copy of the file descriptor oldfd.

       After  successful  return of dup or dup2, the old and new descriptors may be used interchangeably. They share locks, file position pointers
       and flags; for example, if the file position is modified by using lseek on one of the descriptors, the position is  also  changed  for  the
       other.

       The two descriptors do not share the close-on-exec flag, however.

       dup uses the lowest-numbered unused descriptor for the new descriptor.

       dup2 makes newfd be the copy of oldfd, closing newfd first if necessary.

RETURN VALUE

       dup and dup2 return the new descriptor, or -1 if an error occurred (in which case, errno is set appropriately).

ERRORS

       EBADF  oldfd isn't an open file descriptor, or newfd is out of the allowed range for file descriptors.

       EMFILE The process already has the maximum number of file descriptors open and tried to open a new one.

WARNING

       The error returned by dup2 is different to that returned by fcntl(..., F_DUPFD, ...)  when newfd is out of range. On some systems dup2 also
       sometimes returns EINVAL like F_DUPFD.

CONFORMING TO

       SVr4, SVID, POSIX, X/OPEN, BSD 4.3. SVr4 documents additional EINTR and ENOLINK error conditions.  POSIX.1 adds EINTR.

SEE ALSO

       fcntl(2), open(2), close(2)

Linux 1.1.46							    1994-08-21								    DUP(2)