📄 errors.html
字号:
<HTML><HEAD><TITLE>Xlib Programming Manual: Errors</TITLE></HEAD><BODY><H1 ALIGN=center>1.2. Errors</H1>Some functions return <B>Status</B>, an integer error indication.If the function fails, it returns a zero.If the function returns a status of zero,it has not updated the return arguments.<!.IN "Status">Because C does not provide multiple return values, many functions must return their results by writing into client-passed storage. <!.IN "Error" "handling">By default, errors are handled either by a standard library functionor by one that you provide.Functions that return pointers to strings return NULL pointers ifthe string does not exist.<P>The X server reports protocol errors at the time that it detects them.If more than one error could be generated for a given request,the server can report any of them.<P>Because Xlib usually does not transmit requests to the server immediately(that is, it buffers them), errors can be reported much later than theyactually occur.For debugging purposes, however,Xlib provides a mechanism for forcing synchronous behavior (see "<A HREF="../event-handling/protocol-errors/synchronization.html">Enabling or Disabling Synchronization</A>").When synchronization is enabled, errors are reported as they are generated.<P>When Xlib detects an error,it calls an error handler,which your program can provide.If you do not provide an error handler,the error is printed, and your program terminates.<H5 ALIGN=right><I>Next: <A HREF="header.html">Standard Header Files</A></I></H5><HR><ADDRESS><A HREF="http://tronche.com/">Christophe Tronche</A>, <A HREF="mailto:ch.tronche@computer.org">ch.tronche@computer.org</A></ADDRESS></BODY></HTML>⌨️ 快捷键说明
复制代码
Ctrl + C
搜索代码
Ctrl + F
全屏模式
F11
切换主题
Ctrl + Shift + D
显示快捷键
?
增大字号
Ctrl + =
减小字号
Ctrl + -