NAME

       FBB::CerrExtractor - Runs external programs writing standard error

SYNOPSIS

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

DESCRIPTION

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

       CerrExtractor 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      CerrExtractor(size_t bufSize = 100):
              A  bufSize  argument  may  be  specified:  it  defines  the  internal  buffer  size  used  by  the
              CerrExtractor’s streambuf. By default the standard input  and  standard  output  streams  are  not
              handled.

       o      CerrExtractor(Mode mode, size_t bufSize = 100):
              The  mode  argument  must  be  CerrExtractor::CLOSE_STD.  It indicates that the standard input and
              standard error streams are redirected to /dev/null: the child processes cannot read their standard
              input streams and any standard output generated by child processes is ignored. 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 using an
              absolute path (the PATH environment variable isn’t used).  This member immediately returns,  after
              which  information written by the child process to its standard error stream may be extracted from
              the CerrExtractor 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),   cininserter(3bobcat),   coutextractor(3bobcat),   execl(3),   exec(3bobcat),  fork(3bobcat),
       process(3bobcat), stdextractor(3bobcat).

BUGS

       None reported.

BOBCAT PROJECT FILES

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

       o      bobcat_6.04.00-x.dsc: detached signature;

       o      bobcat_6.04.00-x.tar.gz: source archive;

       o      bobcat_6.04.00-x_i386.changes: change log;

       o      libbobcat1_6.04.00-x_*.deb: debian package containing the libraries;

       o      libbobcat1-dev_6.04.00-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).

libbobcat-dev_6.04.00                               2005-2023                        FBB::CerrExtractor(3bobcat)