bionic (3) cerrextractor.3bobcat.gz

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 ttCerrExtractor) 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  contents 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::IFdStreambuf (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 stdandard 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.

MEMBERS

       o      bool 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 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.

DISTRIBUTION FILES

       o      bobcat_4.08.02-x.dsc: detached signature;

       o      bobcat_4.08.02-x.tar.gz: source archive;

       o      bobcat_4.08.02-x_i386.changes: change log;

       o      libbobcat1_4.08.02-x_*.deb: debian package holding the libraries;

       o      libbobcat1-dev_4.08.02-x_*.deb: debian package holding the libraries, headers and manual pages;

       o      http://sourceforge.net/projects/bobcat: public archive location;

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).