Linux Manual Pages

Free Software * Books

Source Code

Free Media

Linux

XShm

HOME

XShm

NAME
SYNTAX
STRUCTURES
DESCRIPTION
SEE ALSO

NAME

XShmQueryExtension, XShmQueryVersion, XShmPixmapFormat, XShmAttach, XShmDetach XShmCreateImage, XShmPutImage, XShmGetImage, XShmCreatePixmap, XShmGetEventBase - X Shared Memory extension functions

SYNTAX

#include <X11/Xlib.h>
#include <sys/ipc.h>
#include <sys/shm.h>
#include <X11/extensions/XShm.h>

		Bool	XShmQueryExtension(
			Display *display);

Bool XShmQueryVersion(

	Display *display;
	int major, minor;
	Bool *pixmaps);

Status XShmPixmapFormat(

Display *display);

Status XShmAttach(

	Display *display;
	XShmSegmentInfo *shminfo);

Status XShmDetach(

	Display *display;
	XShmSegmentInfo *shminfo);

XImage *XShmCreateImage (

	Display *display;
	Visual *visual;
	unsigned int depth;
	int format;
	char *data;
	XShmSegmentInfo *shminfo;
	unsigned int width, height);

Status XShmPutImage(

	Display *display;
	Drawable d;
	GC gc;
	XImage *image;
	int src_x, src_y, dest_x, dest_y;
	unsigned int width, height;
	bool send_event);

Status XShmGetImage (

	Display *display;
	Drawable d;
	XImage *image;
	int x, y;
	unsigned long plane_mask);

Pixmap XShmCreatePixmap(
Display *display;
Drawable d;
char *data;

	XShmSegmentInfo *shminfo;
	unsigned int width, height, depth);

Status XShmGetEventBase(

Display *display);

STRUCTURES

Events:
typedef struct {
int type; /* of event */
unsigned long serial; /* # of last request processed by server*/
Bool send_event; /* true if this came from a SendEvent request*/
Display *display; /* Display the event was read from */
Drawable drawable; /* drawable of request */
int major_code; /* ShmReqCode */
int minor_code; /* X_ShmPutImage */
ShmSeg shmseg; /* the ShmSeg used in the request*/
unsigned long offset; /* the offset into ShmSeg used in the request*/
} XShmCompletionEvent;

a structure of type XShmSegmentInfo :

typedef struct {
ShmSeg shmseg; /* resource id */
int shmid; /* kernel id */
char *shmaddr; /* address in client */
Bool readOnly; /* how the server should attach it */
} XShmSegmentInfo;

DESCRIPTION

XShmQueryExtension checks to see if the shared memory extensions are available for the specified display.

XShmQueryVersion returns the version numbers of the extension implementation. Shared memory pixmaps are supported if the pixmaps argument returns true.

XShmAttach tells the server to attach to your shared memory segment. If all goes well, you will get a non-zero status, back and your XImage is ready for use.

XShmDetach tells the server to detach from your shared memory segment.

XShmPutImage combines an image in memory with a shape of the specified drawable. If XYBitmap format is used, the depth must be one, or a ‘‘BadMatch’’ error results. The foreground pixel in the GC defines the source for the one bits in the image, and the background pixel defines the source for the zero bits. For XYPixmap and ZPixmap, the depth must match the depth of the drawable, or a ‘‘BadMatch’’ error results.

XShmGetImage reads image data into a shared memory XImage where display is the display of interest, drawable is the source drawable, image is the destination XImage, x and y are offsets within the drawable, and plane_mask defines which planes are to be read.

XShmCreateImage allocates the memory needed for an XImage structure for the specified display but does not allocate space for the image itself.

XShmPixmapFormat gets the format for the server. If your application can deal with the server pixmap data format, a shared memory segment and shminfo structure are created.

XShmCreatePixmap points to a pixmap which you can manipulate in all of the usual ways, with the added bonus of being able to edit its contents directly through the shared memory segment.

XShmGetEventBase gets the completion event value.

Opportunity

Personal Opportunity - Free software gives you access to billions of dollars of software at no cost. Use this software for your business, personal use or to develop a profitable skill. Access to source code provides access to a level of capabilities/information that companies protect though copyrights. Open source is a core component of the Internet and it is available to you. Leverage the billions of dollars in resources and capabilities to build a career, establish a business or change the world. The potential is endless for those who understand the opportunity.

Business Opportunity - Goldman Sachs, IBM and countless large corporations are leveraging open source to reduce costs, develop products and increase their bottom lines. Learn what these companies know about open source and how open source can give you the advantage.

Free Software

Free Software provides computer programs and capabilities at no cost but more importantly, it provides the freedom to run, edit, contribute to, and share the software. The importance of free software is a matter of access, not price. Software at no cost is a benefit but ownership rights to the software and source code is far more significant.

Free Office Software - The Libre Office suite provides top desktop productivity tools for free. This includes, a word processor, spreadsheet, presentation engine, drawing and flowcharting, database and math applications. Libre Office is available for Linux or Windows.

Free Books

The Free Books Library is a collection of thousands of the most popular public domain books in an online readable format. The collection includes great classical literature and more recent works where the U.S. copyright has expired. These books are yours to read and use without restrictions.

Source Code - Want to change a program or know how it works? Open Source provides the source code for its programs so that anyone can use, modify or learn how to write those programs themselves. Visit the GNU source code repositories to download the source.

Education

Study at Harvard, Stanford or MIT - Open edX provides free online courses from Harvard, MIT, Columbia, UC Berkeley and other top Universities. Hundreds of courses for almost all major subjects and course levels. Open edx also offers some paid courses and selected certifications.

Linux Manual Pages - A man or manual page is a form of software documentation found on Linux/Unix operating systems. Topics covered include computer programs (including library and system calls), formal standards and conventions, and even abstract concepts.