The libexecstream library

Overview

Libexecstream is a C++ library that allows you to run a child process and have its input, output and error avaliable as standard C++ streams.

Like this:

#include <exec-stream.h>
#include <string>
...
try {
    exec_stream_t es( "perl", "" ); // run perl without any arguments 
    es.in() << "print \"hello world\";"; // and make it print "hello world" 
    es.close_in();                        // after the input was closed 
    std::string hello, world;
    es.out() >> hello; // read the first word of output 
    es.out() >> world; // read the second word 
}catch( std::exception const & e ) {
    std::cerr << "error: "  <<  e.what()  <<  "\n";
}

Features:

• Works on Linux and Windows
• Uses threads
• Does not depend on any other non-standard library
• Distributed as source code only, requires you to compile and link one file into your program
• BSD-style license

Another example:

#include <exec-stream.h>
...
exec_stream_t es;
try {
    // run command to print network configuration, depending on the operating system
    #ifdef _WIN32
        es.start( "ipconfig", "/all" );
    #else
        es.start( "ifconfig", "-a" );
    #endif
    
    std::string s;
    while( std::getline( es.out(), s ).good() ) {
        // do something with s
    }
}catch( std::exception const & e ) {
    std::cerr << "error: "  <<  e.what()  <<  "\n";
}

For more examples see the file test/exec-stream-test.cpp in the source distribution. The interface provided by the library is documented in the reference.

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Installation

Libexecstream is provided in source code form only. In order to use it, you need to compile and link one file, exec-stream.cpp, into your program.

On Linux, libexecstream was tested on Red Hat 9 with gcc compiler. Versions of gcc prior to 3.0 will not work. Make sure that exec-stream.h is found somewhere on the include path, compile exec-stream.cpp as usual, link your program with -lpthread. GCC must be configured with --enable-threads, which is by default on most Linux distributions.

On Windows, libexecstream was tested on XP and 95 flavors with VC++ 7 compiler. VC++ 6 will not work. Make sure that exec-stream.h is found somewhere on the include path, compile exec-stream.cpp as usual, link you program with multi-threaded runtime.

Example makefiles for Windows and Linux (used to build the testsute) are provided in the test directory of the source distribution.

The exec-stream.cpp file includes several platform-dependent implementation files. Selection of platform-specific implementation is done at compile time: when _WIN32 macro is defined (usually by windows compiler) win32 implementation is included, when that macro is not defined, posix implementation is included.

Header file exec-stream.h defines interface of the library and uses only standard C++. It does not include any platform-specific header files.