From: Philipp Stephani Date: Thu, 26 Dec 2019 09:29:21 +0000 (+0100) Subject: Promote function type aliases to the public module API. X-Git-Tag: emacs-28.0.90~7937 X-Git-Url: http://git.eshelyaron.com/gitweb/?a=commitdiff_plain;h=719ad593872b606d2ca6ca5a144e37251c378078;p=emacs.git Promote function type aliases to the public module API. Previously module authors had to define type aliases for module functions and finalizers themselves. This commit adds and documents aliases so that this is no longer necessary. * src/emacs-module.h.in: Add 'emacs_function' and 'emacs_finalizer' type aliases. * src/emacs-module.c: Remove old 'emacs_subr' and 'emacs_finalizer' type aliases. (struct Lisp_Module_Function, module_make_function): Switch from 'emacs_subr' to 'emacs_function'. * doc/lispref/internals.texi (Module Functions): Document and use 'emacs_function' type alias. (Module Values): Document 'emacs_finalizer' type alias. * etc/NEWS: Mention change. --- diff --git a/doc/lispref/internals.texi b/doc/lispref/internals.texi index cf66302a3a9..02180c72a52 100644 --- a/doc/lispref/internals.texi +++ b/doc/lispref/internals.texi @@ -1314,7 +1314,8 @@ subsection describes how to write such @dfn{module functions}. A module function has the following general form and signature: -@deftypefn Function emacs_value module_func (emacs_env *@var{env}, ptrdiff_t @var{nargs}, emacs_value *@var{args}, void *@var{data}) +@deftypefn Function emacs_value emacs_function (emacs_env *@var{env}, ptrdiff_t @var{nargs}, emacs_value *@var{args}, void *@var{data}) +@tindex emacs_function The @var{env} argument provides a pointer to the @acronym{API} environment, needed to access Emacs objects and functions. The @var{nargs} argument is the required number of arguments, which can be @@ -1323,7 +1324,7 @@ of the argument number), and @var{args} is a pointer to the array of the function arguments. The argument @var{data} points to additional data required by the function, which was arranged when @code{make_function} (see below) was called to create an Emacs -function from @code{module_func}. +function from @code{emacs_function}. Module functions use the type @code{emacs_value} to communicate Lisp objects between Emacs and the module (@pxref{Module Values}). The @@ -1338,6 +1339,10 @@ However, if the user typed @kbd{C-g}, or if the module function or its callees signaled an error or exited nonlocally (@pxref{Module Nonlocal}), Emacs will ignore the returned value and quit or throw as it does when Lisp code encounters the same situations. + +The header @file{emacs-module.h} provides the type +@code{emacs_function} as an alias type for a function pointer to a +module function. @end deftypefn After writing your C code for a module function, you should make a @@ -1348,11 +1353,11 @@ normally done in the module initialization function (@pxref{module initialization function}), after verifying the @acronym{API} compatibility. -@deftypefn Function emacs_value make_function (emacs_env *@var{env}, ptrdiff_t @var{min_arity}, ptrdiff_t @var{max_arity}, subr @var{func}, const char *@var{docstring}, void *@var{data}) +@deftypefn Function emacs_value make_function (emacs_env *@var{env}, ptrdiff_t @var{min_arity}, ptrdiff_t @var{max_arity}, emacs_function @var{func}, const char *@var{docstring}, void *@var{data}) @vindex emacs_variadic_function This returns an Emacs function created from the C function @var{func}, -whose signature is as described for @code{module_func} above (assumed -here to be @code{typedef}'ed as @code{subr}). The arguments +whose signature is as described for @code{emacs_function} above. +The arguments @var{min_arity} and @var{max_arity} specify the minimum and maximum number of arguments that @var{func} can accept. The @var{max_arity} argument can have the special value @code{emacs_variadic_function}, @@ -1844,6 +1849,12 @@ represented by @var{arg} to be @var{fin}. If @var{fin} is a finalizer. @end deftypefn +@deftypefun void emacs_finalizer (void *@var{ptr}) +The header @file{emacs-module.h} provides the type +@code{emacs_finalizer} as a type alias for an Emacs finalizer +function. +@end deftypefun + @node Module Misc @subsection Miscellaneous Convenience Functions for Modules diff --git a/etc/NEWS b/etc/NEWS index a1c57929d32..5bd45d72da6 100644 --- a/etc/NEWS +++ b/etc/NEWS @@ -45,6 +45,10 @@ applies, and please also update docstrings as needed. * Lisp Changes in Emacs 28.1 +** The module header 'emacs-module.h' now contains type aliases +'emacs_function' and 'emacs_finalizer' for module functions and +finalizers, respectively. + * Changes in Emacs 28.1 on Non-Free Operating Systems diff --git a/src/emacs-module.c b/src/emacs-module.c index ff1a05450ce..76229137d87 100644 --- a/src/emacs-module.c +++ b/src/emacs-module.c @@ -122,12 +122,6 @@ To add a new module function, proceed as follows: /* Function prototype for the module init function. */ typedef int (*emacs_init_function) (struct emacs_runtime *); -/* Function prototype for module user-pointer finalizers. These - should not throw C++ exceptions, so emacs-module.h declares the - corresponding interfaces with EMACS_NOEXCEPT. There is only C code - in this module, though, so this constraint is not enforced here. */ -typedef void (*emacs_finalizer) (void *); - /* Memory management. */ @@ -466,10 +460,6 @@ module_non_local_exit_throw (emacs_env *env, emacs_value tag, emacs_value value) value_to_lisp (value)); } -/* Function prototype for the module Lisp functions. */ -typedef emacs_value (*emacs_subr) (emacs_env *, ptrdiff_t, - emacs_value *, void *); - /* Module function. */ /* A function environment is an auxiliary structure returned by @@ -486,7 +476,7 @@ struct Lisp_Module_Function /* Fields ignored by GC. */ ptrdiff_t min_arity, max_arity; - emacs_subr subr; + emacs_function subr; void *data; } GCALIGNED_STRUCT; @@ -505,7 +495,7 @@ allocate_module_function (void) static emacs_value module_make_function (emacs_env *env, ptrdiff_t min_arity, ptrdiff_t max_arity, - emacs_subr func, const char *docstring, void *data) + emacs_function func, const char *docstring, void *data) { MODULE_FUNCTION_BEGIN (NULL); diff --git a/src/emacs-module.h.in b/src/emacs-module.h.in index ecbfe28c72c..fbeaebd7956 100644 --- a/src/emacs-module.h.in +++ b/src/emacs-module.h.in @@ -78,6 +78,21 @@ struct emacs_runtime EMACS_ATTRIBUTE_NONNULL(1); }; +/* Type aliases for function pointer types used in the module API. + Note that we don't use these aliases directly in the API to be able + to mark the function arguments as 'noexcept' before C++20. + However, users can use them if they want. */ + +/* Function prototype for the module Lisp functions. These must not + throw C++ exceptions. */ +typedef emacs_value (*emacs_function) (emacs_env *env, ptrdiff_t nargs, + emacs_value *args, + void *data) + EMACS_NOEXCEPT EMACS_ATTRIBUTE_NONNULL (1); + +/* Function prototype for module user-pointer finalizers. These must + not throw C++ exceptions. */ +typedef void (*emacs_finalizer) (void *data) EMACS_NOEXCEPT; /* Possible Emacs function call outcomes. */ enum emacs_funcall_exit