Provided by: libbobcat-dev_3.19.01-1ubuntu1_amd64 bug

NAME

       FBB::Process - Runs external programs

SYNOPSIS

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

DESCRIPTION

       The  FBB::Process  class offers an extensive interface to calling external programs and/or
       scripts from a C++ program (so-called child-processes). The class offers an easy  to  use,
       stream-based  interface  to the standard input, standard output and standard error streams
       of child processes.

       Objects of the class Process use standard process-executing functions, like members of the
       execl(1)  family  or  sh(1)  to  execute  child  processes.  Thus,  child processes can be
       executable programs or shell-scripts.

       The standard input, output and error streams of child processes may  be  accessed  through
       their Process parent objects. Input expected by child processes may be inserted by Process
       objects, and output generated by child processes may be extracted from Process objects.

       When using (output) redirection with the USE_SHELL path specification (see below  for  the
       path  and IOMode specifications), the IGNORE_COUT IOMode (and possibly IGNORE_CERR) should
       normally be specified (see also this man-page’s PIPING section).

       Process objects may repeatedly be used to execute the same or different  child  processes.
       Before  the  next  child  process  is  started,  the  Process  object first terminates its
       currently active child  process.  Alternatively,  a  currently  active  child  process  is
       automatically  ended  if  the  Process  object  goes  out  of  scope,  if  its stop or eoi
       (end-of-information) member is called, or if the eoi  manipulator  is  inserted  into  the
       Process object.

       Programs to be called as child processes may be specified at Process’s constructor-time or
       through Process’s setCommand member. Process constructors (or Process  set-members)  never
       start child processes. Child processes are started through start members or the assignment
       operator.

       Child  processes  may  receive  information  at  their  standard  input  streams   through
       information  inserted into Process objects. In these cases the Process objects must inform
       their child processes that they have received all input. For this the close or eoi  member
       or  the  eoi  manipulator  can  be  used. After calling the close member, the waitForChild
       member should be called as well. This is not necessary if either the eoi member or the eoi
       manipulator is used.

       If  waitForChild is not called (but information sent to the child which could not be fully
       processed by the child process in case the child process terminated as  a  result  of  the
       Process  object  going  out  of  scope),  then  the  operating system issues a Broken pipe
       message, indicating that information in a pipe was lost.

       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 @).

       A  full command specification may be surrounded by backtics (`-characters). These backtick
       characters are removed by the Process object when the command is started.

       Child processes may be allowed a limited amount of  time  (in  seconds)  to  complete.  By
       default no time limit is imposed upon child processes.

       By  default  the  standard input, output and error streams of child processes are accessed
       through their Process parent processes: information inserted into the  Process  object  is
       forwarded  to  the  child  process’s  standard input stream, information sent by the child
       process to its standard output stream can be extracted from its parent Process object, and
       information sent by the child process to its standard error stream may be obtained through
       Process’s childErrStream member.

       If the parent and  child  processes  have  agreed  on  some  communication  process,  then
       information  may  alternatingly be sent to and received from the child process through the
       Process’s  ostream  and  istream  facilities.  Alternatively,   unspecified   amounts   of
       information  written  by  child  processes  may be processed by separate threads (cf. this
       manual page’s EXAMPLES section).

NAMESPACE

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

INHERITS FROM

       FBB::Fork(3bobcat) (private),
       FBB:IOStream(3bobcat) FBB:ProcessEnums

       The  struct  ProcessEnums  defines  enumerations  and  support functions which are used by
       several classes. Its enumerations are documented below; there is no separate  ProcessEnums
       man-page.

ENUMERATIONS

       enum ProcessType:

       The  enum  ProcessType  defines  how a child process is started or located. Its values are
       specified at constructor-time or  through  the  setProcessType  member.  This  enumeration
       defines the following symbolic constants:

       o      NO_PATH:
              The  program  specified as child process is started as specified, without searching
              the elements of the PATH environment variable.

       o      USE_PATH:
              The elements of the PATH environment variable are used when  locating  the  program
              specified as child process.

       o      USE_SHELL:
              The  program  specified  as child process is called using /bin/sh -c. When (output)
              redirection is used with the specified command the IGNORE_COUT IOMode (and possibly
              also the IGNORE_CERR IOMode) should be specified.

       enum IOMode:

       Values of the enum IOMode are used to define which of the child process’s standard streams
       can be accessed through the Process object. Its symbolic constants may be  combined  using
       the bit_or operator. By default CIN | COUT | CERR is used (see below).

       The following symbolic constants are available:

       o      ALL:
              Shortcut for CIN | COUT | CERR.

       o      CIN:
              Information inserted into the Process object is forwarded to its child process.  If
              this is not required then CIN should not be specified.

       o      CERR:
              Information written by the child process to its standard error stream is accessible
              through  Process’s childErrStream member.  If this is not required then CERR should
              not be specified.

       o      COUT:
              Information written by the child process to  its  standard  output  stream  may  be
              directly  be  extracted from the Process object, or from its childOutStream member.
              If this is not required then CERR should not be specified.

       o      DIRECT:
              When starting a child process (see below at the member start) the  current  process
              (i.e.,  the  program defining the Process object) is replaced by the child process,
              inheriting the current process’s standard input and output streams. If this mode is
              specified  in  combination  with  any  other  IOMode (except for STD, see below) an
              std::invalid_argument exception is thrown.

       o      IGNORE_CERR:
              Information written by the child process to its standard error stream  is  sent  to
              /dev/null.  An  std::invalid_argument exception is thrown if this mode is specified
              in combination with DIRECT, CERR and/or MERGE_COUT_CERR.

       o      IGNORE_COUT:
              Information written by the child process to its standard output stream is  sent  to
              /dev/null.  An  std::invalid_argument exception is thrown if this mode is specified
              in combination with COUT, DIRECT and/or MERGE_COUT_CERR.

       o      IGNORE_COUT_CERR:
              Shortcut for IGNORE_CERR | IGNORE_COUT.

       o      MERGE_COUT_CERR:
              Information extracted from the Process object is written by the  child  process  to
              its standard output and standard error streams.  An std::invalid_argument exception
              is thrown if this mode  is  specified  in  combination  with  COUT,  CERR,  DIRECT,
              IGNORE_COUT or IGNORE_CERR.

       o      NONE:
              The Process object does not extract information from or insert information into the
              standard streams of its child process. The child process reads  the  same  standard
              input  stream  and  writes  the  same standard output streams as its parent Process
              object. When this mode is specified in combination with other IOMode values  it  is
              silently ignored.

       enum ChildOutput:
       The  ChildOutput  enumeration  defines values returned by the available member (see below)
       indicating to which standard stream the  child  process  has  written  information.   This
       enumeration defines the following values:

       o      NOTHING_AVAILABLE:
              The child process did not (yet) write any information to its standard streams;

       o      CHILD_COUT:
              The  child process wrote information to its standard output stream which is waiting
              for extraction.

       o      CHILD_CERR:
              The child process wrote information to its standard error stream which  is  waiting
              for  extraction.   The latter two values may be combined using the bit_or operator.
              The bit_and operator,returning a bool value can be used to test whether information
              on a specific output stream is available.

PROCESS PARAMETERS

       Four  process  parameters may be specified: the sizes of the stream buffers which are used
       when communicating with child processes; to specify which of the standard streams of child
       processes  can be accessed from the Process object combinations of IOMode values are used;
       to specify how child programs are found a  ProcessType  value  is  used;  to  specify  the
       maximum time (in seconds) the child program is allowed to run a size_t values is used.

       By  default, the stream buffers hold 200 bytes; all the child’s standard streams (standard
       input, output and error) are accessible from the  Parent  process;  the  PATH  environment
       variable  is not used to locate the child program; and the child processes will be allowed
       an unlimited amount of time to run.

       After constructing a  Process  object  all  default  parameters  may  be  modified.  These
       parameters  may  either  be  altered  for  a  single process or a Process object’s general
       defaults may be modified. The set* members (see below) may be used to change  the  default
       process  parameters. When parameters are specified otherwise, they will only be active for
       the next process.

CONSTRUCTORS

       The command provided to the following constructors  may  be  the  (initial  part  of  the)
       specification of an external program to run. When the program is eventually started it may
       start and end with a back-tick (`).  The  back-ticks  will  be  removed  just  before  the
       specified program is executed.

       Child  processes  are  not started automatically following Process object constructions. A
       start member or the assignment operator (see below) is used to start the  specified  child
       process.

       The mode parameter that is defined for the second through fourth constructor is defined as
       a size_t for backward compatibility reasons.  Internally,  this  argument  is  immediately
       converted  to  a  Process::IOMode  value,  silently ignoring values which do not represent
       valid IOMode values. Multiple IOMode values may be combined using the bit-or operator.

       After constructing a Process  object  its  parameters  can  be  changed  using  set-member
       functions, function call operators or start members.

       o      Process(std::string const &cmd = ""):
              This constructor is used to specify the (initial part of a) command to execute from
              a Process object. Default values are used for the process parameters  (see  section
              PROCESS PARAMETERS).

       o      Process(size_t mode, std::string const &cmd = ""):
              This  constructor  requires the specification of the object’s IOMode, and it can be
              used to specify the (initial part of a) command to execute from a  Process  object.
              Default  values  are used for the remaining process parameters (see section PROCESS
              PARAMETERS).

       o      Process(size_t mode, ProcessType type, std::string const &cmd = ""):
              This constructor requires the specification of the object’s IOMode and ProcessType,
              and  it  can  be  used to specify the (initial part of a) command to execute from a
              Process object.  Default values are used for the remaining process parameters  (see
              section PROCESS PARAMETERS).

       o      Process(size_t  mode,  ProcessType type, size_t timeLimit, std::string const &cmd =
              ""):
              This constructor requires the specification of the  object’s  IOMode,  ProcessType,
              and  child  process  time  limit. The (initial part of a) command to execute from a
              Process object may optionally be specified. The default process parameter  is  used
              for  the  sizes  of  the  internally  used  stream  buffers  (see  section  PROCESS
              PARAMETERS).

       o      Process(IOMode  mode,  ProcessType  type,  size_t  timeLimit,  size_t   bufferSize,
              std::string const &cmd = ""):
              This  constructor  requires  the specification of the object’s IOMode, ProcessType,
              child process time limit, and size of  the  internally  used  stream  buffers.  The
              (initial  part  of  a)  command  to execute from a Process object may optionally be
              specified. Note that this constructor’s mode parameter does  not  accept  a  size_t
              argument.  The class Process does not offer copy or move constructors.

OVERLOADED OPERATORS

       o      Process &operator<<(Type value):
              This operator inserts value into the child’s standard input stream. I.e., the child
              process reads value from its standard input. A  value  of  any  type  that  can  be
              inserted  into an ostream can be inserted into a Process object. Nothing happens if
              the member is used when the child process has  terminated.  The  behavior  of  this
              operator is undefined unless IOMode CIN was specified.

       o      Process &operator>>(Type value):
              This operator extracts value from the child’s standard output stream and optionally
              (if IOMode MERGE_COUT_CERR was specified) from  the  child’s  error  stream.  I.e.,
              value  may  be  extracted  from  Process  objects.  A value of any type that can be
              extracted from an istream can be extracted from a Process object.  Nothing  happens
              if  the  member is used when the child process has terminated. The behavior of this
              operator is undefined unless IOMode COUT or MERGE_COUT_CERR was specified.

       o      Process &operator+=(std::string const &):
              This operator adds the provided std::string object to the currenly defined  command
              specification  of a Process object. The member operator+= does not add a separating
              blank space between the currently stored command  specification  and  the  text  to
              append.  It merely adds its right-hand side string to the command stored so far. It
              does not affect a currently running child process.

       o      int operator=(std::string const &cmd):
              The operator= member defines cmd as the  stored command in a Process object.

              Before starting the child process a possibly active child process is first  stopped
              by calling stop. It returns stop’s return value.

       o      Process &operator()(IOMode mode):
              This operator changes the the Process object’s IOMode parameter. A reference to the
              Process object is returned, allowing constructions like

                  process(Process::COUT) = "/bin/cat";

              to start a new child process with the specified IOMode.

       o      Process &operator()(IOMode mode, ProcessType type):
              This  operator  changes  the  Process  object’s  IOMode  and  ProcessType   process
              parameters.

       o      Process &operator()(size_t mode, ProcessType type, size_t timeLimit):
              This  operator  changes the Process object’s mentioned process parameters, silently
              converting the size_t mode to an IOMode value. The currently specified default size
              of the stream buffers is kept as-is.

       o      Process   &operator()(IOMode  mode,  ProcessType  type,  size_t  timeLimit,  size_t
              bufferSize):
              This operator changes all of the Process object’s process parameters.

       o      Process &operator|(Process &lhs, Process &rhs):
              This operator implements process piping: information sent b  lhs  to  its  standard
              output becomes the rhs’s standard input. The operator returns rhs.

              This  operator  mimics the piping-operator supported by most command-shell programs
              and should not be confused with the binary-or operator.  The  operator  starts  the
              lhs’s   child  process, but the rhs’s child process (and thus pipe processing) must
              explicitly be started.

              Since operator| is left-associative and rhs is  returned  piping  can  be  chained,
              allowing constructions like p1 | p2 | p3, where p1, p2 and p3 are Process objects.

              The following idiom can be used to start the execution of a chain of processes: (p1
              | p2 | p3).start(). Alternatively, the following two-step procedure can be used:

                  p1 | p2 | p3;
                  p3.start();

              If p1 specifies Process::CIN then this IOMode is forwared to the final  process  of
              the  chain  of  processes.  It  is not necessary to specify Process::CIN for p3. In
              fact, most IOMode flags of processes passed to operator| are ignored  or  modified.
              Acceptable  IOModes  are  Process::IGNORE_CERR  and Process::CERR (accepted for all
              processes), Process::CIN (accepted  for  the  first  process  of  the  chain),  and
              Process::COUT  (for  the  last  process of the chain). After connecting a series of
              processes using operator| all input and  output  (except  for  the  standard  error
              streams)  is handled through the last process: if Process::CIN is specified for the
              first process then this mode is transferred to the  last  process,  so  information
              inserted into the last process enters the pipe through the first process’s standard
              input.

              The next example illustrates how input can be inserted into the first process  from
              a main process and sent to the standard output stream by the final process:

                  using namespace std;
                  using namespace FBB;

                  Process p1(Process::CIN, "/bin/cat");
                  Process p2("/bin/cat");
                  Process p3(Process::STD, "/bin/cat");

                  p1 | p2 | p3;

                  p3.start();

                  p3 << cin.rdbuf() << eoi;

              Note  that  when  specifying  multiple  commands  using  the piping operator (’|’),
              traditionally USE_SHELL had to be specified, as the traditional piping operator  is
              a shell-feature. Process’s operator| handles I/O piping itself, and thus avoids the
              additional  shell  process.   The  default  overloaded  copy  and  move  assignment
              operators are not available.

MEMBERS

       o      bool active():
              This  member  returns  true  if the child process is currently running and false if
              not.

       o      size_t available():
              This member returns immediately. Its return value indicates whether any information
              can  be  obtained  from  the  child  process as value(s) from the enum ChildOutput.
              NOTHING_AVAILABLE is returned if no information is ready for extraction. CHILD_COUT
              is  returned  if  information  from  the  child process’s standard output stream is
              available; CHILD_CERR is returned if information from the child process’s  standard
              error  stream is available; CHILD_COUT | CHILD_CERR is returned if information from
              both the standard output and standard  error  streams  is  available.  The  bit_and
              operator,  returning  a  bool  value, can be used to determine which stream has any
              pending information. E.g.,

                  if (process.available() & Process::CHILD_COUT)
                      cout << "Process has child standard output available";

       o      size_t bufSize() const:
              This member returns the default size of  the  stream  buffers  that  are  used  for
              communication  with  child  processes.  If called while a child process is actually
              running, then the value returned by this member may differ from the value that  was
              actually  used when starting the child process, as the default value may be altered
              by a function call operator just before starting the child process.

       o      std::istream &cerr():
              This member should be avoided. Use childErrStream instead.

       o      std::istream &childErrStream():
              If Process::CERR was specified then this member interfaces to the child’s  standard
              error  stream. By extracting the information from childErrStream the parent process
              retrieves the information sent by its child process to its standard error stream.

       o      std::istream &childOutStream():
              If  Process::COUT  or  Process::MERGE_COUT_CERR  was  specified  then  this  member
              interfaces  to  the  child’s  standard output stream. By extracting the information
              from childOutStream the parent process retrieves the information sent by its  child
              process to its standard output stream. Alternatively, this information may directly
              be extracted from the Process object itself, but this member does not  require  the
              use of a static_cast to disambiguate the intended stream buffer in statements like

                  cout << process.childOutStream().rdbbuf()

       o      void close():
              This  member  closes  the  child’s  input  stream.  In  situations  where the child
              continuously reads information from its standard input stream this  member  can  be
              used to inform the child process that input has terminated. This member should only
              be used when IOMode CIN was specified for  the  currently  running  child  process;
              otherwise  its  behavior is undefined. Alternatively, the eoi member or manipulator
              may be used.

       o      void eoi():
              This member closes the child’s input stream, and then calls  waitForChild  to  wait
              for  the  child  process  to  end. In situations where the child continuously reads
              information from its standard input stream this member can be used  to  inform  the
              child  process  that  input  has  terminated.  This member should only be used when
              IOMode CIN was specified for the currently running  child  process;  otherwise  its
              behavior  is  undefined.  Alternatively, the close member or eoi manipulator may be
              used.

       o      std::istream &errStream():
              This member may be used to extract information written by the child process to  its
              standard  error  stream.   This  member  should  only  be used when IOMode CERR was
              specified for the currently  running  child  process;  otherwise  its  behavior  is
              undefined.

       o      IOMode ioMode() const:
              This member returns the default IOMode. If called while a child process is actually
              running, then the value returned by this member may differ from the value that  was
              actually  used when starting the child process, as the default value may be altered
              by a function call operator just before starting the child process.

       o      ProcessType processType() const:
              This member returns the default ProcessType of child proceses. If  called  while  a
              child  process  is  actually  running,  then  the value returned by this member may
              differ from the value that was actually used when starting the  child  process,  as
              the  default  value may be altered by a function call operator just before starting
              the child process.

       o      size_t timeLimit() const:
              This member returns the default time limit  (in  seconds)  of  child  processes.  A
              return  value  of  zero indicates that no time limit is enforced. If called while a
              child process is actually running, then the  value  returned  by  this  member  may
              differ  from  the  value that was actually used when starting the child process, as
              the default value may be altered by a function call operator just  before  starting
              the child process.

       o      void setBufSize(size_t bufSize):
              This  member  changes the default stream buffer size that is used for communication
              with child processes. A zero byte buffer size is silently changed into one. The new
              default value will be used when starting the next child process.

       o      void setCommand(std::string const &cmd):
              The  setCommand  member  (re)defines  the (initial part of a) child process command
              specification.

              This member does not actually start the child process, and operator+= may  be  used
              to  append  additional  text to the command specification. Also, this member may be
              used when a child process is currently active: its use does not affect a  currently
              running child process.

       o      void setIOMode(iomode mode):
              This  member  changes  the  default IOMode. The new default value will be used when
              starting the next child process.

       o      void setProcessType(ProcessType type):
              This member changes the default ProcessType. The new default  value  will  be  used
              when starting the next child process.

       o      void setTimeLimit(size_t timeLimit):
              This  member  changes  the default execution time limit (in seconds). No time limit
              will be imposed upon child processes if timeLimit 0 is specified. The  new  default
              value will be used when starting the next child process.

       o      void start():
              The  currently  specified  command  is  started  using the Process object’s process
              parameters.

              Having specified a command to start, the first white-space delimited element of the
              specified  command  is  used  as  the  name of the program to start. If the program
              should be called through sh(1), the USE_SHELL ProcessType or a system member should
              be used.

              If  a child process does not terminate by itself, then it is terminated when it has
              run for its alloted time; when the Process  object’s  start  or  stop  members  are
              called;  when the object’s assignment operator is used; or when the object goes out
              of scope.

       o      void start(IOMode mode):
              The currently  specified  command  is  started  using  the  specified  IOMode,  but
              otherwise  using  the currently configured Process object’s process parameters. The
              specified IOMode is only used for the child process that is started by this member.

       o      void start(IOMode mode, ProcessType type):
              The  currently  specified  command  is  started  using  the  specified  IOMode  and
              ProcessType,  but otherwise using the currently configured Process object’s process
              parameters. The specified process parameter values are  only  used  for  the  child
              process that is started by this member.

       o      void start(size_t mode, Program program, size_t timeLimit):
              The currently specified command is started using the specified IOMode, ProcessType,
              and time limit (silently converting the size_t mode to an IOMode value), and  using
              the  currently  configured  Process  object’s  stream  buffer  size  parameter. The
              specified process parameter values are only used for  the  child  process  that  is
              started by this member.

       o      void start(IOMode mode, Program program, size_t timeLimit, size_t bufferSize):
              The  currently specified command is started using the specified process parameters.
              The specified parameter values are only used for the child process that is  started
              by this member.

       o      void showMode(char const *lab) const:
              This member displays the label lab, followed by the current process ID, followed by
              the child process’s process  ID,  followed  by  a  textual  representation  of  the
              currently active IOMode.

       o      std::string const &str() const:
              This   member   returns   the   contents  of  the  current  child  process  command
              specification. It shows the command as it will be (or has been) executed by  start,
              system or the assignment operator.

       o      void system():
              This  member  executes  the  currently  stored command as a command to sh(1).  When
              using system redirections can be included in the command itself (this  renders  the
              redirected  streams  implied  by  the  current  IOMode)  useless. The currently set
              process parameters are used when sh(1) is executed.

       o      void system(IOMode mode):
              This member executes the currently stored command as a command to sh(1) (cf. system
              above) using the specified IOMode rather than the current default IOMode setting.

       o      void system(IOMode mode, size_t timeLimit):
              This member executes the currently stored command as a command to sh(1) (cf. system
              above) using the specified IOMode and time limit.

       o      void system(IOMode mode, size_t timeLimit, size_t bufSize):
              This member executes the currently stored command as a command to sh(1) (cf. system
              above) using the specified IOMode, time limit, and stream buffer size values.

       o      int stop():
              This member terminates a currently active child process. The child process is twice
              sent a SIG_TERM signal, followed by a SIG_KILL  signal.  This  member  returns  the
              exit-value  of  the  child process that was stopped. Its operation and return value
              are undefined if called without a running child process.

              Following stop a new command may be called using start, system  or  the  assignment
              operator  (see  earlier). Those members first calls stop.  When the intention is to
              start another child process, then there’s no need to call  stop  explicitly.  Also,
              stop is called when the Process object goes out of scope.

       o      int waitForChild():
              This  member is inherited from the class FBB::Fork. It waits for a child process to
              end. It is called to prevent  premature  termination  of  a  child  process  before
              calling stop. It is not always necessary to call waitForChild. E.g., when a process
              writes to its standard output stream and all output has been read  then  the  child
              process can be stopped without calling waitForChild.

MANIPULATOR

       o      FBB::eoi:
              This  manipulator  may  be  inserted into a Process object for which IOMode CIN was
              specified. It closes the child’s input stream, and then calls waitForChild to  wait
              for  the  child  process  to  end. In situations where the child continuously reads
              information from its standard input stream this member can be used  to  inform  the
              child  process  that input has terminated. Alternatively, Process object’s close or
              eoi members may be used.

EXAMPLES

       The first example shows how a program only producing  output  can  be  called.  Its  child
       process simply is /bin/ls:

       int main()
       {
           Process process(Process::COUT, "/bin/ls -Fla");

           process.start();
           cout << process.childOutStream().rdbuf();
       }

       The  next  example  shows  how  a child program can be given a limited amount of execution
       time: lines entered at the keyboard are echoed to the standard output stream for at most 5
       seconds:

       int main()
       {
           Process process(Process::CIN | Process::COUT, "/bin/cat");
           process.setTimeLimit(5);

           process.start();

           while (true)
           {
               cout << "? ";
               string line;
               if (not getline(cin, line))
                   return 0;

               process << line << endl;        // to /bin/cat
               line.clear();

               if (not getline(process, line))    // from /bin/cat
                   break;

               cout << "Received: " << line << endl;
           }

           cout << "/bin/cat time limit of 5 seconds reached: child process ended\n";
       }

       The  final  example  shows  how  multi threading can be used to access the child program’s
       standard output and standard error streams through the Process object:

       void collect(ostream *outStream, streambuf *rdbuf)
       {
           *outStream << rdbuf << flush;
       }

       int main()
       {
           string cmd(getcwd(0, 0));
           cmd += "/cincoutcerr";

           Process all(Process::ALL, cmd);

           all.start();

           thread outThread(collect, &cout, all.childOutStream().rdbuf());
           thread errThread(collect, &cerr, all.childErrStream().rdbuf());

           all << cin.rdbuf() << eoi;

           outThread.join();
           errThread.join();
       }

       Additional examples are found in the distribution’s bobcat/process/driver directory.

FILES

       bobcat/process - defines the class interface

SEE ALSO

       bobcat(7), execle(3), fork(3bobcat), iostream(3fork), sh(1)

BUGS

       With the release of Bobcat 1.21.1 the class Process  was  completely  rewritten.  The  new
       implementation,  however, should not affect existing programs other than that Process will
       no longer impose a limited time-to-live upon child processes. The interface was  enlarged,
       but  this  should  not  affect existing programs. The internal organization of the Process
       class has changed though, requiring recompilation of sources defining Process  class  type
       objects and linking dynamically to the Bobcat library.

       With  the  release  of  Bobcat  2.11.0 another major modification of Process was realized.
       Although Process’s internal organization was again modified this does not affect exeisting
       programs  using  Process  objects.  No  recompilation of existing sources using Process is
       required.

DISTRIBUTION FILES

       o      bobcat_3.19.01-x.dsc: detached signature;

       o      bobcat_3.19.01-x.tar.gz: source archive;

       o      bobcat_3.19.01-x_i386.changes: change log;

       o      libbobcat1_3.19.01-x_*.deb: debian package holding the libraries;

       o      libbobcat1-dev_3.19.01-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).