+++ /dev/null
-@c Copyright (C) 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
-@c 1999, 2000, 2001 Free Software Foundation, Inc.
-@c This is part of the GCC manual.
-@c For copying conditions, see the file gcc.texi.
-
-@node VMS
-@chapter Using GCC on VMS
-
-@c prevent bad page break with this line
-Here is how to use GCC on VMS@.
-
-@menu
-* Global Declarations:: How to do globaldef, globalref and globalvalue with
- GCC.
-* VMS Misc:: Misc information.
-@end menu
-
-@node Global Declarations
-@section Global Declarations and VMS
-
-@findex GLOBALREF
-@findex GLOBALDEF
-@findex GLOBALVALUEDEF
-@findex GLOBALVALUEREF
-GCC does not provide the @code{globalref}, @code{globaldef} and
-@code{globalvalue} keywords of VAX-C@. You can get the same effect with
-an obscure feature of GAS, the GNU assembler. (This requires GAS
-version 1.39 or later.) The following macros allow you to use this
-feature in a fairly natural way:
-
-@smallexample
-#ifdef __GNUC__
-#define GLOBALREF(TYPE,NAME) \
- TYPE NAME \
- asm ("_$$PsectAttributes_GLOBALSYMBOL$$" #NAME)
-#define GLOBALDEF(TYPE,NAME,VALUE) \
- TYPE NAME \
- asm ("_$$PsectAttributes_GLOBALSYMBOL$$" #NAME) \
- = VALUE
-#define GLOBALVALUEREF(TYPE,NAME) \
- const TYPE NAME[1] \
- asm ("_$$PsectAttributes_GLOBALVALUE$$" #NAME)
-#define GLOBALVALUEDEF(TYPE,NAME,VALUE) \
- const TYPE NAME[1] \
- asm ("_$$PsectAttributes_GLOBALVALUE$$" #NAME) \
- = @{VALUE@}
-#else
-#define GLOBALREF(TYPE,NAME) \
- globalref TYPE NAME
-#define GLOBALDEF(TYPE,NAME,VALUE) \
- globaldef TYPE NAME = VALUE
-#define GLOBALVALUEDEF(TYPE,NAME,VALUE) \
- globalvalue TYPE NAME = VALUE
-#define GLOBALVALUEREF(TYPE,NAME) \
- globalvalue TYPE NAME
-#endif
-@end smallexample
-
-@noindent
-(The @code{_$$PsectAttributes_GLOBALSYMBOL} prefix at the start of the
-name is removed by the assembler, after it has modified the attributes
-of the symbol). These macros are provided in the VMS binaries
-distribution in a header file @file{GNU_HACKS.H}. An example of the
-usage is:
-
-@example
-GLOBALREF (int, ijk);
-GLOBALDEF (int, jkl, 0);
-@end example
-
-The macros @code{GLOBALREF} and @code{GLOBALDEF} cannot be used
-straightforwardly for arrays, since there is no way to insert the array
-dimension into the declaration at the right place. However, you can
-declare an array with these macros if you first define a typedef for the
-array type, like this:
-
-@example
-typedef int intvector[10];
-GLOBALREF (intvector, foo);
-@end example
-
-Array and structure initializers will also break the macros; you can
-define the initializer to be a macro of its own, or you can expand the
-@code{GLOBALDEF} macro by hand. You may find a case where you wish to
-use the @code{GLOBALDEF} macro with a large array, but you are not
-interested in explicitly initializing each element of the array. In
-such cases you can use an initializer like: @code{@{0,@}}, which will
-initialize the entire array to @code{0}.
-
-A shortcoming of this implementation is that a variable declared with
-@code{GLOBALVALUEREF} or @code{GLOBALVALUEDEF} is always an array. For
-example, the declaration:
-
-@example
-GLOBALVALUEREF(int, ijk);
-@end example
-
-@noindent
-declares the variable @code{ijk} as an array of type @code{int [1]}.
-This is done because a globalvalue is actually a constant; its ``value''
-is what the linker would normally consider an address. That is not how
-an integer value works in C, but it is how an array works. So treating
-the symbol as an array name gives consistent results---with the
-exception that the value seems to have the wrong type. @strong{Don't
-try to access an element of the array.} It doesn't have any elements.
-The array ``address'' may not be the address of actual storage.
-
-The fact that the symbol is an array may lead to warnings where the
-variable is used. Insert type casts to avoid the warnings. Here is an
-example; it takes advantage of the ISO C feature allowing macros that
-expand to use the same name as the macro itself.
-
-@example
-GLOBALVALUEREF (int, ss$_normal);
-GLOBALVALUEDEF (int, xyzzy,123);
-#ifdef __GNUC__
-#define ss$_normal ((int) ss$_normal)
-#define xyzzy ((int) xyzzy)
-#endif
-@end example
-
-Don't use @code{globaldef} or @code{globalref} with a variable whose
-type is an enumeration type; this is not implemented. Instead, make the
-variable an integer, and use a @code{globalvaluedef} for each of the
-enumeration values. An example of this would be:
-
-@example
-#ifdef __GNUC__
-GLOBALDEF (int, color, 0);
-GLOBALVALUEDEF (int, RED, 0);
-GLOBALVALUEDEF (int, BLUE, 1);
-GLOBALVALUEDEF (int, GREEN, 3);
-#else
-enum globaldef color @{RED, BLUE, GREEN = 3@};
-#endif
-@end example
-
-@node VMS Misc
-@section Other VMS Issues
-
-@cindex exit status and VMS
-@cindex return value of @code{main}
-@cindex @code{main} and the exit status
-GCC automatically arranges for @code{main} to return 1 by default if
-you fail to specify an explicit return value. This will be interpreted
-by VMS as a status code indicating a normal successful completion.
-Version 1 of GCC did not provide this default.
-
-GCC on VMS works only with the GNU assembler, GAS@. You need version
-1.37 or later of GAS in order to produce value debugging information for
-the VMS debugger. Use the ordinary VMS linker with the object files
-produced by GAS@.
-
-@cindex shared VMS run time system
-@cindex @file{VAXCRTL}
-Under previous versions of GCC, the generated code would occasionally
-give strange results when linked to the sharable @file{VAXCRTL} library.
-Now this should work.
-
-A caveat for use of @code{const} global variables: the @code{const}
-modifier must be specified in every external declaration of the variable
-in all of the source files that use that variable. Otherwise the linker
-will issue warnings about conflicting attributes for the variable. Your
-program will still work despite the warnings, but the variable will be
-placed in writable storage.
-
-@cindex name augmentation
-@cindex case sensitivity and VMS
-@cindex VMS and case sensitivity
-Although the VMS linker does distinguish between upper and lower case
-letters in global symbols, most VMS compilers convert all such symbols
-into upper case and most run-time library routines also have upper case
-names. To be able to reliably call such routines, GCC (by means of
-the assembler GAS) converts global symbols into upper case like other
-VMS compilers. However, since the usual practice in C is to distinguish
-case, GCC (via GAS) tries to preserve usual C behavior by augmenting
-each name that is not all lower case. This means truncating the name
-to at most 23 characters and then adding more characters at the end
-which encode the case pattern of those 23. Names which contain at
-least one dollar sign are an exception; they are converted directly into
-upper case without augmentation.
-
-Name augmentation yields bad results for programs that use precompiled
-libraries (such as Xlib) which were generated by another compiler. You
-can use the compiler option @samp{/NOCASE_HACK} to inhibit augmentation;
-it makes external C functions and variables case-independent as is usual
-on VMS@. Alternatively, you could write all references to the functions
-and variables in such libraries using lower case; this will work on VMS,
-but is not portable to other systems. The compiler option @samp{/NAMES}
-also provides control over global name handling.
-
-Function and variable names are handled somewhat differently with G++.
-The GNU C++ compiler performs @dfn{name mangling} on function
-names, which means that it adds information to the function name to
-describe the data types of the arguments that the function takes. One
-result of this is that the name of a function can become very long.
-Since the VMS linker only recognizes the first 31 characters in a name,
-special action is taken to ensure that each function and variable has a
-unique name that can be represented in 31 characters.
-
-If the name (plus a name augmentation, if required) is less than 32
-characters in length, then no special action is performed. If the name
-is longer than 31 characters, the assembler (GAS) will generate a
-hash string based upon the function name, truncate the function name to
-23 characters, and append the hash string to the truncated name. If the
-@samp{/VERBOSE} compiler option is used, the assembler will print both
-the full and truncated names of each symbol that is truncated.
-
-The @samp{/NOCASE_HACK} compiler option should not be used when you are
-compiling programs that use libg++. libg++ has several instances of
-objects (i.e. @code{Filebuf} and @code{filebuf}) which become
-indistinguishable in a case-insensitive environment. This leads to
-cases where you need to inhibit augmentation selectively (if you were
-using libg++ and Xlib in the same program, for example). There is no
-special feature for doing this, but you can get the result by defining a
-macro for each mixed case symbol for which you wish to inhibit
-augmentation. The macro should expand into the lower case equivalent of
-itself. For example:
-
-@example
-#define StuDlyCapS studlycaps
-@end example
-
-These macro definitions can be placed in a header file to minimize the
-number of changes to your source code.
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