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HP C++
HP C++ Class Library Reference Manual
Chapter 5 Messages Package
The Messages package provides a way to retrieve messages stored in a catalog or
file that is separate from your program.
It consists of a single class,
Messages
, that
retrieves the text of a message.
Processing a message file on an OpenVMS system requires a message set number and
a message number. A message set number is an OpenVMS message identification
code, including a facility code (bits 16 through 27) and a facility-specific bit
(bit 15); all other bits should be 0.
A message number is an integer from 1 to 8191.
To process the message file, use the OpenVMS Message Utility (see the
OpenVMS Message Utility Manual for details) and link the resulting
object code into one of the following:
- Your program
- A shareable image that your program is linked against
- A shareable image that is then specified with the
set message
command
Messages class
Retrieves message text for a message number.
Header File
#include <messages.hxx>
Alternative Header
None.
Declaration
class Messages
{
public:
Messages(const char *filename_arg, int set_arg = 0,
const char *default_file_location_arg = (const char *)(NULL));
~Messages();
const char *text(int msg_arg, const char *fallback_text_arg,
int set_arg = 0);
};
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Constructors and Destructors
Messages(const char *filename_arg, int set_arg, const char
*default_file_location_arg)
Constructs a
Messages
object. set_arg specifies the message number to set; a value
of 0 specifies that the default set be used. filename_arg and
default_file_location_arg are ignored.
~Messages()
Deletes a
Messages
object.
Member Function
const char *text(int msg_arg, const char *fallback_text_arg, int
set_arg)
Returns the text of the message specified by the msg_arg
argument. The fallback_text_arg argument indicates the text to
return if the message cannot be found. The set_arg argument
specifies the message set number; a value of 0 causes the system to use
the set number provided to the constructor.
Depending on the process defaults, the facility, error severity, and
message identification code may be appended to the beginning of the
message (for example,
%CXXL-W-E_ONEXT
, prefixed to
Can't delete an object that is on a list.
).
Example
The following is a sample message source file:
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.TITLE MESSAGES_EXAMPLE_MSG Example messages -- VMS message catalog
.IDENT '1.0'
.FACILITY EXAMPLE, 1 /PREFIX=EXAMPLE_
.BASE 0
.SEVERITY WARNING ! we just want a 0 in the severity field
SET <> ! message set number
.SEVERITY ERROR
EXAMPLE_ERROR <This is an example error message>
.END
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Entering the following OpenVMS Message Utility commands set the
appropriate options and compile this file:
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$ set message/nofac/nosev/noid
$ message/lis MESSAGES_EXAMPLE_MSG
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The following program retrieves the sample error message:
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#include <iostream.hxx>
#include <messages.hxx>
const char *message_file_name = (const char *)(NULL);
const char *message_file_location = (const char *)(NULL);
#pragma __extern_model __save
#pragma __extern_model __globalvalue
extern int EXAMPLE_SET;
#pragma __extern_model __restore
int message_set_example = EXAMPLE_SET;
Messages m_example (message_file_name, message_set_example,
message_file_location);
int main()
{
cout <<
"text of example message 1: " <<
m_example.text(1, "fallback message 1") <<
"\n";
cout <<
"text of example message 2: " <<
m_example.text(2, "fallback message 2") <<
"\n";
return 0;
}
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The following compiler command compiles the program:
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$ cxx/lis MESSAGES_EXAMPLE
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Entering the following link and run sequence retrieves the text of the
error message and displays the second fallback message:
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$ link MESSAGES_EXAMPLE,MESSAGES_EXAMPLE_MSG
$ run/nodeb messages_example
text of example message 1: This is an example error message
text of example message 2: fallback message 2
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