Here is how to use GCC on VMS@.
@menu
-* Include Files and VMS:: Where the preprocessor looks for the include files.
* Global Declarations:: How to do globaldef, globalref and globalvalue with
GCC.
* VMS Misc:: Misc information.
@end menu
-@node Include Files and VMS
-@section Include Files and VMS
-
-@cindex include files and VMS
-@cindex VMS and include files
-@cindex header files and VMS
-Due to the differences between the filesystems of Unix and VMS, GCC
-attempts to translate file names in @samp{#include} into names that VMS
-will understand. The basic strategy is to prepend a prefix to the
-specification of the include file, convert the whole filename to a VMS
-filename, and then try to open the file. GCC tries various prefixes
-one by one until one of them succeeds:
-
-@enumerate
-@item
-The first prefix is the @samp{GNU_CC_INCLUDE:} logical name: this is
-where GNU C header files are traditionally stored. If you wish to store
-header files in non-standard locations, then you can assign the logical
-@samp{GNU_CC_INCLUDE} to be a search list, where each element of the
-list is suitable for use with a rooted logical.
-
-@item
-The next prefix tried is @samp{SYS$SYSROOT:[SYSLIB.]}. This is where
-VAX-C header files are traditionally stored.
-
-@item
-If the include file specification by itself is a valid VMS filename, the
-preprocessor then uses this name with no prefix in an attempt to open
-the include file.
-
-@item
-If the file specification is not a valid VMS filename (i.e.@: does not
-contain a device or a directory specifier, and contains a @samp{/}
-character), the preprocessor tries to convert it from Unix syntax to
-VMS syntax.
-
-Conversion works like this: the first directory name becomes a device,
-and the rest of the directories are converted into VMS-format directory
-names. For example, the name @file{X11/foobar.h} is
-translated to @file{X11:[000000]foobar.h} or @file{X11:foobar.h},
-whichever one can be opened. This strategy allows you to assign a
-logical name to point to the actual location of the header files.
-
-@item
-If none of these strategies succeeds, the @samp{#include} fails.
-@end enumerate
-
-Include directives of the form:
-
-@example
-#include foobar
-@end example
-
-@noindent
-are a common source of incompatibility between VAX-C and GCC@. VAX-C
-treats this much like a standard @code{#include <foobar.h>} directive.
-That is incompatible with the ISO C behavior implemented by GCC: to
-expand the name @code{foobar} as a macro. Macro expansion should
-eventually yield one of the two standard formats for @code{#include}:
-
-@example
-#include "@var{file}"
-#include <@var{file}>
-@end example
-
-If you have this problem, the best solution is to modify the source to
-convert the @code{#include} directives to one of the two standard forms.
-That will work with either compiler. If you want a quick and dirty fix,
-define the file names as macros with the proper expansion, like this:
-
-@example
-#define stdio <stdio.h>
-@end example
-
-@noindent
-This will work, as long as the name doesn't conflict with anything else
-in the program.
-
-Another source of incompatibility is that VAX-C assumes that:
-
-@example
-#include "foobar"
-@end example
-
-@noindent
-is actually asking for the file @file{foobar.h}. GCC does not
-make this assumption, and instead takes what you ask for literally;
-it tries to read the file @file{foobar}. The best way to avoid this
-problem is to always specify the desired file extension in your include
-directives.
-
-GCC for VMS is distributed with a set of include files that is
-sufficient to compile most general purpose programs. Even though the
-GCC distribution does not contain header files to define constants
-and structures for some VMS system-specific functions, there is no
-reason why you cannot use GCC with any of these functions. You first
-may have to generate or create header files, either by using the public
-domain utility @code{UNSDL} (which can be found on a DECUS tape), or by
-extracting the relevant modules from one of the system macro libraries,
-and using an editor to construct a C header file.
-
-A @code{#include} file name cannot contain a DECNET node name. The
-preprocessor reports an I/O error if you attempt to use a node name,
-whether explicitly, or implicitly via a logical name.
-
@node Global Declarations
@section Global Declarations and VMS
git://gcc.gnu.org / gcc.git / commitdiff