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Full Discussion: Cannot correctly connect multi-stage C command pipe (among others) (FYI: a lot of code)
Homework and Emergencies Homework & Coursework Questions Cannot correctly connect multi-stage C command pipe (among others) (FYI: a lot of code) Post 302787959 by Corona688 on Sunday 31st of March 2013 02:15:19 PM
Old 03-31-2013
Code:
      dup2(prev[0],0);
      dup2(prev[1],1);

You are attaching the reading end of the pipe to standard input. This makes sense.

You are attaching the writing end of the pipe to standard output. This makes sense.

However, you are doing both to the same pipe. This does not make sense. To picture the loop you've made:

Code:
 /-->grep---\
 \----------/

Where what you actually want is:

Code:
command1 --> command2 --> command3

command1 writes into the write end of pipe A. command2 reads from pipe A, writes to pipe B. command3 reads from pipe B, writes to the terminal.
Last edited by Corona688; 03-31-2013 at 03:26 PM..
 

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LEARN ABOUT DEBIAN

std::hash

std::hash< _Tp >(3cxx)													    std::hash< _Tp >(3cxx)

NAME

       std::hash< _Tp > -

SYNOPSIS

       Inherits std::__hash_base< _Result, _Arg >.

   Public Types
       typedef _Arg argument_type
       typedef _Result result_type

   Public Member Functions
       size_t operator() (_Tp __val) const
       template<> size_t operator() (bool __val) const
       template<> size_t operator() (char __val) const
       template<> size_t operator() (signed char __val) const
       template<> size_t operator() (unsigned char __val) const
       template<> size_t operator() (wchar_t __val) const
       template<> size_t operator() (char16_t __val) const
       template<> size_t operator() (char32_t __val) const
       template<> size_t operator() (short __val) const
       template<> size_t operator() (int __val) const
       template<> size_t operator() (long __val) const
       template<> size_t operator() (long long __val) const
       template<> size_t operator() (unsigned short __val) const
       template<> size_t operator() (unsigned int __val) const
       template<> size_t operator() (unsigned long __val) const
       template<> size_t operator() (unsigned long long __val) const
       template<> size_t operator() (float __val) const
       template<> size_t operator() (double __val) const
       template<> size_t operator() (long double __val) const

Detailed Description
   template<typename _Tp>struct std::hash< _Tp >
       Primary class template hash.

       Definition at line 58 of file functional_hash.h.

Author
       Generated automatically by Doxygen for libstdc++ from the source code.

libstdc++							  Tue Nov 27 2012					    std::hash< _Tp >(3cxx)
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