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_6.02.02-x.dsc: detached signature;

       o      bobcat_6.02.02-x.tar.gz: source archive;

       o      bobcat_6.02.02-x_i386.changes: change log;

       o      libbobcat1_6.02.02-x_*.deb: debian package containing the libraries;

       o      libbobcat1-dev_6.02.02-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).