dup(2)                                                               dup(2)




 NAME    [Toc]    [Back]
      dup - duplicate an open file descriptor

 SYNOPSIS    [Toc]    [Back]
      #include <unistd.h>

      int dup(int fildes);

 DESCRIPTION    [Toc]    [Back]
      fildes is a file descriptor obtained from a creat(), open(), dup(),
      fcntl(), or pipe() system call.  dup() returns a new file descriptor
      having the following in common with the original:

           +  Same open file (or pipe).

           +  Same file pointer (i.e., both file descriptors share one file
              pointer).

           +  Same access mode (read, write or read/write).

           +  Same file status flags (see fcntl(2), F_DUPFD).

      The new file descriptor is set to remain open across exec() system
      calls.  See fcntl(2).

      The file descriptor returned is the lowest one available.

 RETURN VALUE    [Toc]    [Back]
      Upon successful completion, the file descriptor is returned as a nonnegative
 integer.  Otherwise, a value of -1 is returned and errno is
      set to indicate the error.

 ERRORS    [Toc]    [Back]
      dup() fails if one or more of the following is true:

      [EBADF]                  fildes is not a valid open file descriptor.

      [EMFILE]                 Request violates the maximum number of open
                               file descriptors.

 AUTHOR    [Toc]    [Back]
      dup() was developed by AT&T and HP.

 SEE ALSO    [Toc]    [Back]
      close(2), creat(2), dup2(2), exec(2), fcntl(2), open(2), pipe(2).

 STANDARDS CONFORMANCE    [Toc]    [Back]
      dup(): AES, SVID2, SVID3, XPG2, XPG3, XPG4, FIPS 151-2, POSIX.1


 Hewlett-Packard Company            - 1 -   HP-UX 11i Version 2: August 2003