XtAppAddSignal
XtAppAddSignal
NAMESYNTAX
ARGUMENTS
DESCRIPTION
SEE ALSO
NAME
XtAppAddSignal, XtRemoveSignal, XtNoticeSignal − register and remove a signal source
SYNTAX
|
XtSignalId XtAppAddSignal(XtAppContext app_context, XtSignalCallbackProc proc, XtPointer client_data); |
||
|
void XtRemoveSignal(XtSignalId id); |
||
|
void XtNoticeSignal(XtSignalId id); |
ARGUMENTS
app_context
Specifies the application context.
client_data
Specifies the argument that is to be passed to the specified procedure when a signal has been raised.
|
id |
Specifies the ID returned from the corresponding XtAppAddSignal call. | ||
|
proc |
Specifies the procedure that is to be called when the signal has been raised. |
DESCRIPTION
The XtAppAddSignal function initiates a mechanism for handling signals within the context of the Intrinsics. Prior to establishing an operating system dependent signal handler the application may call XtAppAddSignal and store the returned id in a place accessible to the signal handler.
Upon receipt of a signal from the operating system, the application may call XtNoticeSignal passing the id returned by the call to XtAppAddSignal.
XtNoticeSignal is the only Intrinsics function that can safely be called from a signal handler. If XtNoticeSignal is called multiple times before the Intrinsics are able to invoke the registered callback, the callback is only called once. Logically the Intrinsics maintain ‘‘pending’’ for each registered callback. This flag is initially False and is set to True by XtNoticeSignal; the Intrinsics invoke the callback whenever the flag is True, and the flag is set to False just before the callback is invoked.
The XtRemoveSignal function is called to remove the specified Intrinsics signal handler. The client should disable the source of the signal before calling XtRemoveSignal.
SEE ALSO
XtAppAddTimeOut(3Xt),XtAppAddInput(3Xt),XtAppAddWorkProc(3Xt)
X Toolkit Intrinsics − C Language Interface
Xlib − C Language X Interface
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.
