oracular (3) stdextractor.3bobcat.gz

NAME

       FBB::StdExtractor - Runs external programs writing standard error

SYNOPSIS

       #include <bobcat/cerrextractor>
       Linking option: -lbobcat

DESCRIPTION

       The  FBB::StdExtractor  class  offers  a  basic  interface for calling external programs (so-called child
       processes) writing their standard output and error streams.  The  standard  input  stream  of  the  child
       processes  are  by  default not handled by StdExtractor objects. The child’s standard output and standard
       error streams are read through the StdExtractor object: information written by the child process to these
       streams  is  extracted  or  read from StdExtractor object. The PATH environment variable is not used when
       calling child processes: child process programs must be specified using paths.

       StdExtractor objects may repeatedly be used to execute the same or different child processes.

       Arguments passed to child processes may be surrounded by double or single quotes. Arguments surrounded by
       double  quotes  have  their  double quotes removed, while interpreting any escape-sequences that may have
       been used within. Arguments surrounded by single quotes have their single quotes removed, while accepting
       their  content  as-is. In addition unquoted escape-sequences may be specified: those escape sequences are
       evaluated and replaced by their intended characters (e.g., \100 is converted to @).

NAMESPACE

       FBB
       All constructors, members, operators and manipulators, mentioned in this man-page,  are  defined  in  the
       namespace FBB.

INHERITS FROM

       FBB::Exec (private), FBB::IFdBuf (private), std::istream

CONSTRUCTOR

       o      StdExtractor(size_t bufSize = 100):
              A  bufSize  argument  may  be  specified:  it  defines  the  internal  buffer  size  used  by  the
              StdExtractor’s streambuf. By default the stdandard input  stream is not handled.

       o      CoutExtractor(Mode mode, size_t bufSize = 100):
              The mode argument must be StdExtractor::CLOSE_STD. It indicates that the standard input stream  is
              redirected  to  /dev/null: the child processes cannot read their standard input streams. A bufSize
              argument may be specified:  it  defines  the  internal  buffer  size  used  by  the  CinInserter’s
              streambuf.

       Copy and move constructors (and assignment operators) are not available.

MEMBERS

       o      void execute(std::string const &cmd):
              The argument specifies the command to execute: the command itself must be specified as a path (the
              PATH environment variable isn’t used). This member immediately returns,  after  which  information
              written  by  the  child process to its standard output and standard error streams may be extracted
              from the StdExtractor object.

              Once execute has returned it can be called again, either using the same or another command.

              Arguments passed to the program to be executed as child process may optionally be specified  using
              single or double quotes, as described in this man-page’s DESCRIPTION section.

       o      int ret() const:
              Once  execute  has  returned  this  member provides the actual exit code of the child process. Its
              value equals -1 before the first exectue call.

PROTECTED MEMBER

       o      Pipe &childOutPipe():
              If derived classes need to override the redirections-members then they probabaly  need  access  to
              the  pipe  written by the child process. This member provides a reference to that pipe. By default
              the parent process reads information from the pipe, while the child process inserts  its  standard
              error output into the pipe.

EXAMPLE

       #include <iostream>

       #include <bobcat/cerrextractor>

       using namespace std;
       using namespace FBB;

       int main()
       {
           CerrExtractor extractor;

           extractor.execute("/bin/cat driver.cc");

           cout << extractor.rdbuf();

           cerr << "Returning: " << extractor.ret() << "\n"
                   "again:\n";

           extractor.execute("/bin/cat driver.cc");

           cout << extractor.rdbuf();

           cerr << "Returning: " << extractor.ret() << ’\n’;

       }

FILES

       bobcat/cerrextractor - provides the class interface

SEE ALSO

       bobcat(7), cerrextractor(3bobcat), cininserter(3bobcat), coutextractor(3bobcat), execl(3), exec(3bobcat),
       fork(3bobcat), process(3bobcat).

BUGS

       None reported.

BOBCAT PROJECT FILES

       o      https://fbb-git.gitlab.io/bobcat/: gitlab project page;

       o      bobcat_6.06.01-x.dsc: detached signature;

       o      bobcat_6.06.01-x.tar.gz: source archive;

       o      bobcat_6.06.01-x_i386.changes: change log;

       o      libbobcat1_6.06.01-x_*.deb: debian package containing the libraries;

       o      libbobcat1-dev_6.06.01-x_*.deb: debian package containing the libraries, headers and manual pages;

BOBCAT

       Bobcat is an acronym of `Brokken’s Own Base Classes And Templates’.

COPYRIGHT

       This is free software, distributed under the terms of the GNU General Public License (GPL).

AUTHOR

       Frank B. Brokken (f.b.brokken@rug.nl).