csu3_am335x/EVSE/GPL/plc-utils.LNX.2.1.20/source/docbook2/oerror.xml

<chapter id='oerror'>
	<title>
		Class oerror
		</title>
	<section id="oerror-class" >
		<title>
			Introduction
			</title>
		<para>
			This class implements a standard means of displaying system error messages. Class methods may be replaced or adapted to support either a console or a windowing environment.
			</para>
		<para>
			This class is declared in <ulink url='oerror.hpp.html'>oerror.hpp</ulink> and defined in <ulink url='oerror.cpp.html'>oerror.cpp</ulink>.
			</para>
		<section id="oerror-inheritance">
			<title>
				Inheritance
				</title>
			<para>
				None.
				</para>
			</section>
		<section id="oerror-dependence">
			<title>
				Dependence
				</title>
			<para>
				This references header file <ulink url='types.h.html'>types.h</ulink> to define data type <quote>errno_t</quote>.
				</para>
			<para>
				This classes references external character string <varname>program_name</varname> which must be defined and initialized somewhere in the environment. The simplest method is to define a global constant character pointer to the basename of <varname>argv</varname>[<constant>0</constant>] in function main().
				</para>
			</section>
		</section>
	<section id="oerror-properties">
		<title>
			Properties
			</title>
		<para>
			None.
			</para>
		</section>
	<section id="oerror-methods">
		<title>
			Methods
			</title>
		<para>
			</para>
		<section id="oerror-error">
			<title>
				oerror::error
				</title>
			<funcsynopsis>
				<funcprototype>
  					<funcdef>oerror &amp; <function>oerror::error</function></funcdef>
    					<paramdef>signed <parameter>status</parameter></paramdef> 
   					<paramdef>errno_t <parameter>number</parameter></paramdef> 
    					<paramdef>errno_t <parameter>format</parameter></paramdef> 
   					<paramdef><parameter>...</parameter></paramdef> 
					</funcprototype>
				</funcsynopsis>
			<para>
				Print an error message on <constant>stderr</constant> and optionally terminate the program. The message consists of the program name, system error message and a program error message. This method behaves the same as the <productname>GNU/Linux</productname> <application>error</application> function.
				</para>
			<variablelist>
				<varlistentry>
					<term>
						status
						</term>
					<listitem>
						<para>
							The program exit status. if status is 0 then this method will return to the caller after printing an error message. Otherwise, the program will exit with this value after printing the message.
							</para>
						</listitem>
					</varlistentry>
				<varlistentry>
					<term>
						errno
						</term>
					<listitem>
						<para>
							The error code. This is normally the value of global variable <varname>errno</varname> set by system functions to indicate the cause of an error condition. If argument <varname>number</varname> is <constant>0</constant> then no system error message is printed. Otherwise,  the system error message will appear  
							</para>
						</listitem>
					</varlistentry>
				<varlistentry>
					<term>
						format
						</term>
					<listitem>
						<para>
							The format string. The content is the same as required by standard library function printf().
							</para>
						</listitem>
					</varlistentry>
				<varlistentry>
					<term>
						...
						</term>
					<listitem>
						<para>
							A variable length argument list. On <productname>GNU/Linux</productname> systems, the <application>gcc</application> compiler checks to ensure the number and type of each argument actually match the corresponding format string specification.
							</para>
						</listitem>
					</varlistentry>
				</variablelist>
			</section>
		</section>
	</chapter>