devfs_set_cdevpriv(9) [debian man page]

DEVFS_CDEVPRIV							       LOCAL							    DEVFS_CDEVPRIV

NAME

     devfs_set_cdevpriv, devfs_get_cdevpriv, devfs_clear_cdevpriv -- manage per-open filedescriptor data for devices

SYNOPSIS

     #include <sys/param.h>
     #include <sys/conf.h>

     typedef void (*cdevpriv_dtr_t)(void *data);

     int
     devfs_get_cdevpriv(void **datap);

     int
     devfs_set_cdevpriv(void *priv, cdevpriv_dtr_t dtr);

     void
     devfs_clear_cdevpriv(void);

DESCRIPTION

     The devfs_xxx_cdevpriv() family of functions allows the cdev driver methods to associate some driver-specific data with each user process
     open(2) of the device special file.  Currently, functioning of these functions is restricted to the context of the cdevsw switch method calls
     performed as devfs(5) operations in response to system calls that use filedescriptors.

     The devfs_set_cdevpriv() function associates a data pointed by priv with current calling context (filedescriptor).  The data may be retrieved
     later, possibly from another call performed on this filedescriptor, by the devfs_get_cdevpriv() function.	The devfs_clear_cdevpriv() disas-
     sociates previously attached data from context.  Immediately after devfs_clear_cdevpriv() finished operating, the dtr callback is called,
     with private data supplied data argument.

     On the last filedescriptor close, system automatically arranges devfs_clear_cdevpriv() call.

     If successful, the functions return 0.

     The function devfs_set_cdevpriv() returns the following values on error:

     [ENOENT]		The current call is not associated with some filedescriptor.

     [EBUSY]		The private driver data is already associated with current filedescriptor.

     The function devfs_get_cdevpriv() returns the following values on error:

     [EBADF]		The current call is not associated with some filedescriptor.

     [ENOENT]		The private driver data was not associated with current filedescriptor, or devfs_clear_cdevpriv() was called.

SEE ALSO

     open(2), close(2), devfs(5), kern_openat(9)

HISTORY

     The devfs_cdevpriv() family of functions first appeared in FreeBSD 7.1.

BSD
								 September 8, 2008							       BSD

FBB::Pipe(3bobcat)						   Error handler						FBB::Pipe(3bobcat)

NAME

       FBB::Pipe - Defines a system level pipe

SYNOPSIS

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

DESCRIPTION

       FBB::Pipe  objects  may	be  used to construct a pipe. FBB::Pipe objects offer a simple interface to the reading and writing ends of pipes.
       FBB::Pipe objects are object-wrappers around the pipe(2) system call.

NAMESPACE

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

INHERITS FROM

       -

CONSTRUCTORS

       o      Pipe():
	      The default Pipe() constructor constructs a basic pipe, calling pipe(2).

	      This constructor throws an Errno exception if the default Pipe constructor did not properly complete.   The  thrown  Errno  object's
	      which() member shows the system's errno value set by the failing pipe(2) function.

       o      Pipe(int const *fd):
	      This  constructor  expects  two  file descriptors, which already define a pipe, stored at fd. Following the construction of the Pipe
	      object the array at by fd is no longer used by the Pipe object.  The copy constructor is available.

       Note that when the pipe goes out of scope, no close(2) operation is performed on the pipe's ends. If the pipe should be closed by the desc-
       tructor, derive a class from Pipe(3bobcat), whose destructor performs the required closing-operation.

MEMBER FUNCTIONS

       o      int readFd() const:
	      Returns the pipe's file descriptor that is used for reading

       o      void readFrom(int filedescriptor):
	      Sets up redirection from the internal read filedescriptor to the given filedescriptor: information is read from the FBB::Pipe object
	      when reading from the provided filedescriptor.

       o      void readFrom(int const *filedescriptors, size_t n):
	      Sets up redirection from the internal read filedescriptor to the given filedescriptors:  information  is	read  from  the  FBB::Pipe
	      object when reading from any of the n provided filedescriptors (experimental).

       o      int readOnly():
	      Closes the writing end of the pipe, returns the reading end's file descriptor.

       o      void verify() const:
	      Obsoleted, will be removed in a future Bobcat release.

       o      int writeFd() const:
	      Returns the pipe's file descriptor that is used for writing

       o      void writtenBy(int filedescriptor):
	      Sets  up	redirection  from  the internal write filedescriptor to the given filedescriptor: information is  written to the FBB::Pipe
	      object when writing to the provided filedescriptor.

       o      void writtenBy(int const *filedescriptors, size_t n):
	      Sets up redirection from the internal write filedescriptor to the given filedescriptors: information is  written	to  the  FBB::Pipe
	      object when writing to each of the n provided filedescriptors.

       o      int writeOnly():
	      Closes the reading end of the pipe, returns the writing end's file descriptor.

PROTECTED ENUMERATION

       The RW protected enumeration has the following elements:

       o      READ:
	      The index in d_fd[] (see below) of the element holding the pipe's reading file descriptor;

       o      WRITE:
	      The index in d_fd[] (see below) of the element holding the pipe's writing file descriptor

PROTECTED DATA

       o      int d_fd[2]:
	      The  array holding the pipe's file descriptors. The READ element contains the pipe's reading file descriptor, the WRITE element con-
	      tains the pipe's writing file descriptor,

EXAMPLE

	   #include <bobcat/pipe>
	   #include <sys/types.h>
	   #include <sys/wait.h>
	   #include <unistd.h>
	   #include <iostream>
	   #include <string>

	   using namespace std;
	   using namespace FBB;

	   int main()
	   {
	       Pipe p;			       // construct a pipe

	       cout << "Read file descriptor: " << p.getReadFd() << endl;
	       cout << "Write file descriptor: " << p.getWriteFd() << endl;

	       int pid = fork();

	       if (pid == -1)
		   return 1;

	       if (!pid)		       //child
	       {
		   p.readFrom(STDIN_FILENO);   // read what goes into the pipe

		   string s;

		   getline(cin, s);
		   cout << "CHILD: Got `" << s << "'" << endl;

		   getline(cin, s);
		   cout << "CHILD: Got `" << s << "'" << endl;

		   return 0;
	       }

	       p.writtenBy(STDOUT_FILENO);	// write to the pipe via cout

	       cout << "first line" << endl;
	       cout << "second line" << endl;

	       waitpid(pid, 0, 0);

	       return 0;
	   }

FILES

       bobcat/pipe - defines the class interface

SEE ALSO

       bobcat(7), pipe(2), mkfifo(3)

BUGS

       Note that when the pipe goes out of scope, no close(2) operation is performed on the pipe's ends. If the pipe should be closed by the desc-
       tructor, derive a class from Pipe(3bobcat), whose destructor performs the required closing-operation.

DISTRIBUTION FILES

       o      bobcat_3.01.00-x.dsc: detached signature;

       o      bobcat_3.01.00-x.tar.gz: source archive;

       o      bobcat_3.01.00-x_i386.changes: change log;

       o      libbobcat1_3.01.00-x_*.deb: debian package holding the libraries;

       o      libbobcat1-dev_3.01.00-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).

libbobcat1-dev_3.01.00-x.tar.gz 				     2005-2012							FBB::Pipe(3bobcat)