[Guile-commits] 77/86: Minor __scm.h reformatting

[Andy Wingo]

wingo pushed a commit to branch master
in repository guile.

commit 32d94b6a8b8540b773e69ad4c780ab1f9f841283
Author: Andy Wingo <address@hidden>
Date:   Wed Jun 20 15:49:15 2018 +0200

    Minor __scm.h reformatting
    
    * libguile/__scm.h: Reorder header and use GNU syntax for comments.
---
 libguile/__scm.h | 363 +++++++++++++++++++++----------------------------------
 1 file changed, 139 insertions(+), 224 deletions(-)

diff --git a/libguile/__scm.h b/libguile/__scm.h
index de2c329..9f4bed8 100644
--- a/libguile/__scm.h
+++ b/libguile/__scm.h
@@ -20,65 +20,80 @@
  * 02110-1301 USA
  */
 
-
-
-/**********************************************************************
- This file is Guile's central public header.
-
- When included by other files, this file should preceed any include
- other than __scm.h.
 
- Under *NO* circumstances should new items be added to the global
- namespace (via adding #define, typedef, or similar to this file) with
- generic names.  This usually means that any new names should be
- prefixed by either SCM_ or GUILE_.  i.e. do *not* #define HAVE_FOO or
- SIZEOF_BAR.  See configure.in, gen-scmconfig.h.in, and
- gen-scmconfig.c for examples of how to properly handle this issue.
- The main documentation is in gen-scmconfig.c.
- **********************************************************************/
+
 
 #include <stdint.h>
 
 /* What did the configure script discover about the outside world?  */
 #include "libguile/scmconfig.h"
 
+
 
 
-/* {Compiler hints}
- *
- * The following macros are used to provide additional information for the
- * compiler, which may help to do better error checking and code
- * optimization.  A second benefit of these macros is, that they also provide
- * additional information to the developers.
- */
+/* SCM_API is a macro prepended to all function and data definitions
+   which should be exported from libguile. */
+#if defined BUILDING_LIBGUILE && defined HAVE_VISIBILITY
+# define SCM_API extern __attribute__((__visibility__("default")))
+#elif defined BUILDING_LIBGUILE && defined _MSC_VER
+# define SCM_API __declspec(dllexport) extern
+#elif defined _MSC_VER
+# define SCM_API __declspec(dllimport) extern
+#else
+# define SCM_API extern
+#endif
 
-/* The macro SCM_NORETURN indicates that a function will never return.
- * Examples:
- *   1) int foo (char arg) SCM_NORETURN;
- */
+/* The SCM_INTERNAL macro makes it possible to explicitly declare a
+   function as having "internal" linkage.  However our current tack on
+   this problem is to use GCC 4's -fvisibility=hidden, making functions
+   internal by default, and then SCM_API marks them for export.  */
+#define SCM_INTERNAL  extern
+
+/* The SCM_DEPRECATED macro is used in declarations of deprecated
+   functions or variables.  Defining `SCM_BUILDING_DEPRECATED_CODE'
+   allows deprecated functions to be implemented in terms of deprecated
+   functions, and allows deprecated functions to be referred to by
+   `scm_c_define_gsubr ()'.  */
+#if !defined (SCM_BUILDING_DEPRECATED_CODE) && defined __GNUC__
+# define SCM_DEPRECATED  SCM_API __attribute__ ((__deprecated__))
+#else
+# define SCM_DEPRECATED  SCM_API
+#endif
+
+/* The SCM_NORETURN macro indicates that a function will never return.
+   Examples:
+     1) int foo (char arg) SCM_NORETURN;  */
 #ifdef __GNUC__
-#define SCM_NORETURN __attribute__ ((__noreturn__))
+# define SCM_NORETURN __attribute__ ((__noreturn__))
 #else
-#define SCM_NORETURN
+# define SCM_NORETURN
 #endif
 
-/* The macro SCM_UNUSED indicates that a function, function argument or
- * variable may potentially be unused.
- * Examples:
- *   1) static int unused_function (char arg) SCM_UNUSED;
- *   2) int foo (char unused_argument SCM_UNUSED);
- *   3) int unused_variable SCM_UNUSED;
- */
+/* The SCM_UNUSED macro indicates that a function, function argument or
+   variable may potentially be unused.
+   Examples:
+     1) static int unused_function (char arg) SCM_UNUSED;
+     2) int foo (char unused_argument SCM_UNUSED);
+     3) int unused_variable SCM_UNUSED;  */
 #ifdef __GNUC__
-#define SCM_UNUSED __attribute__ ((unused))
+# define SCM_UNUSED __attribute__ ((unused))
 #else
-#define SCM_UNUSED
+# define SCM_UNUSED
 #endif
 
+/* The SCM_MALLOC macro can be used in function declarations to tell the
+   compiler that a function may be treated as if any non-NULL pointer it
+   returns cannot alias any other pointer valid when the function
+   returns.  */
+#ifdef __GNUC__
+# define SCM_MALLOC  __attribute__ ((__malloc__))
+#else
+# define SCM_MALLOC
+#endif
 
-/* The SCM_EXPECT macros provide branch prediction hints to the compiler.  To
- * use only in places where the result of the expression under "normal"
- * circumstances is known.  */
+/* The SCM_EXPECT macros provide branch prediction hints to the
+   compiler.  To use only in places where the result of the expression
+   under "normal" circumstances is known.  */
 #ifdef __GNUC__
 # define SCM_EXPECT    __builtin_expect
 #else
@@ -88,204 +103,113 @@
 #define SCM_LIKELY(_expr)    SCM_EXPECT ((_expr), 1)
 #define SCM_UNLIKELY(_expr)  SCM_EXPECT ((_expr), 0)
 
-/* The SCM_INTERNAL macro makes it possible to explicitly declare a function
- * as having "internal" linkage.  However our current tack on this problem is
- * to use GCC 4's -fvisibility=hidden, making functions internal by default,
- * and then SCM_API marks them for export. */
-#define SCM_INTERNAL  extern
-
-/* The SCM_DEPRECATED macro is used in declarations of deprecated functions
- * or variables.  Defining `SCM_BUILDING_DEPRECATED_CODE' allows deprecated
- * functions to be implemented in terms of deprecated functions, and allows
- * deprecated functions to be referred to by `scm_c_define_gsubr ()'.  */
-#if !defined (SCM_BUILDING_DEPRECATED_CODE) && defined __GNUC__
-# define SCM_DEPRECATED  SCM_API __attribute__ ((__deprecated__))
-#else
-# define SCM_DEPRECATED  SCM_API
-#endif
-
-/* The SCM_ALIGNED macro, when defined, can be used to instruct the compiler
- * to honor the given alignment constraint.  */
-/* Sun Studio supports alignment since Sun Studio 12 */
+/* The SCM_ALIGNED macro, when defined, can be used to instruct the
+   compiler to honor the given alignment constraint.  Sun Studio
+   supports alignment since Sun Studio 12.  */
 #if defined __GNUC__ || (defined( __SUNPRO_C ) && (__SUNPRO_C - 0 >= 0x590))
 # define SCM_ALIGNED(x)  __attribute__ ((aligned (x)))
 #elif defined __INTEL_COMPILER
 # define SCM_ALIGNED(x)  __declspec (align (x))
 #else
-/* Don't know how to align things.  */
 # undef SCM_ALIGNED
 #endif
 
-/* The SCM_MALLOC macro can be used in function declarations to tell the
- * compiler that a function may be treated as if any non-NULL pointer it 
returns
- * cannot alias any other pointer valid when the function returns.  */
-#ifdef __GNUC__
-# define SCM_MALLOC  __attribute__ ((__malloc__))
+/* Thread-local storage (TLS).  */
+#ifdef SCM_HAVE_THREAD_STORAGE_CLASS
+# define SCM_THREAD_LOCAL __thread
 #else
-# define SCM_MALLOC
+# define SCM_THREAD_LOCAL
 #endif
 
-
-
-/* SCM_API is a macro prepended to all function and data definitions
-   which should be exported from libguile. */
-
-#if defined BUILDING_LIBGUILE && defined HAVE_VISIBILITY
-# define SCM_API extern __attribute__((__visibility__("default")))
-#elif defined BUILDING_LIBGUILE && defined _MSC_VER
-# define SCM_API __declspec(dllexport) extern
-#elif defined _MSC_VER
-# define SCM_API __declspec(dllimport) extern
-#else
-# define SCM_API extern
-#endif
 
 
 
-/* {Debugging Options}
- *
- * These compile time options determine whether to include code that is only
- * useful for debugging guile itself or C level extensions to guile.  The
- * common prefix for all option macros of this kind is "SCM_DEBUG_".  It is
- * guaranteed that a macro named SCM_DEBUG_XXX is always defined (typically to
- * either 0 or 1), i. e. there is no need to test for the undefined case.
- * This allows to use these definitions comfortably within code, as in the
- * following example:
- *   #define FOO do { if (SCM_DEBUG_XXX) bar(); else baz(); } while (0)
- * Any sane compiler will remove the unused branch without any performance
- * penalty for the resulting code.
- *
- * Note:  Some SCM_DEBUG_XXX options are not settable at configure time.
- * To change the value of such options you will have to edit this header
- * file or give suitable options to make, like:
- *   make all CFLAGS="-DSCM_DEBUG_XXX=1 ..."
- */
-
-
 /* The value of SCM_DEBUG determines the default for most of the not yet
- * defined debugging options.  This allows, for example, to enable most of the
- * debugging options by simply defining SCM_DEBUG as 1.
- */
+   defined debugging options.  This allows, for example, to enable most
+   of the debugging options by simply defining SCM_DEBUG as 1.  */
 #ifndef SCM_DEBUG
 #define SCM_DEBUG 0
 #endif
 
-/* If SCM_DEBUG_PAIR_ACCESSES is set to 1, accesses to cons cells will be
- * exhaustively checked.  Note:  If this option is enabled, guile will run
- * slower than normally.
- */
+/* If SCM_DEBUG_PAIR_ACCESSES is set to 1, accesses to cons cells will
+   be exhaustively checked.  Note:  If this option is enabled, guile
+   will run slower than normally.  */
 #ifndef SCM_DEBUG_PAIR_ACCESSES
 #define SCM_DEBUG_PAIR_ACCESSES SCM_DEBUG
 #endif
 
-/* If SCM_DEBUG_REST_ARGUMENT is set to 1, functions that take rest arguments
- * will check whether the rest arguments are actually passed as a proper list.
- * Otherwise, if SCM_DEBUG_REST_ARGUMENT is 0, functions that take rest
- * arguments will take it for granted that these are passed as a proper list.
- */
+/* If SCM_DEBUG_REST_ARGUMENT is set to 1, functions that take rest
+   arguments will check whether the rest arguments are actually passed
+   as a proper list.  Otherwise, if SCM_DEBUG_REST_ARGUMENT is 0,
+   functions that take rest arguments will take it for granted that
+   these are passed as a proper list.  */
 #ifndef SCM_DEBUG_REST_ARGUMENT
 #define SCM_DEBUG_REST_ARGUMENT SCM_DEBUG
 #endif
 
-/* The macro SCM_DEBUG_TYPING_STRICTNESS indicates what level of type checking
- * shall be performed with respect to the use of the SCM datatype.  The macro
- * may be defined to one of the values 0, 1 and 2.
- *
- * A value of 0 means that there will be no compile time type checking, since
- * the SCM datatype will be declared as an integral type.  This setting should
- * only be used on systems, where casting from integral types to pointers may
- * lead to loss of bit information.
- *
- * A value of 1 means that there will an intermediate level of compile time
- * type checking, since the SCM datatype will be declared as a pointer to an
- * undefined struct.  This setting is the default, since it does not cost
- * anything in terms of performance or code size.
- *
- * A value of 2 provides a maximum level of compile time type checking since
- * the SCM datatype will be declared as a struct.  This setting should be used
- * for _compile time_ type checking only, since the compiled result is likely
- * to be quite inefficient.  The right way to make use of this option is to do
- * a 'make clean; make CFLAGS=-DSCM_DEBUG_TYPING_STRICTNESS=2', fix your
- * errors, and then do 'make clean; make'.
- */
+/* The macro SCM_DEBUG_TYPING_STRICTNESS indicates what level of type
+   checking shall be performed with respect to the use of the SCM
+   datatype.  The macro may be defined to one of the values 0, 1 and 2.
+  
+   A value of 0 means that there will be no compile time type checking,
+   since the SCM datatype will be declared as an integral type.  This
+   setting should only be used on systems, where casting from integral
+   types to pointers may lead to loss of bit information.
+  
+   A value of 1 means that there will an intermediate level of compile
+   time type checking, since the SCM datatype will be declared as a
+   pointer to an undefined struct.  This setting is the default, since
+   it does not cost anything in terms of performance or code size.
+  
+   A value of 2 provides a maximum level of compile time type checking
+   since the SCM datatype will be declared as a struct.  This setting
+   should be used for _compile time_ type checking only, since the
+   compiled result is likely to be quite inefficient.  The right way to
+   make use of this option is to do a 'make clean; make
+   CFLAGS=-DSCM_DEBUG_TYPING_STRICTNESS=2', fix your errors, and then do
+   'make clean; make'.  */
 #ifndef SCM_DEBUG_TYPING_STRICTNESS
 #define SCM_DEBUG_TYPING_STRICTNESS 1
 #endif
 
 
 
-/* {Feature Options}
- *
- * These compile time options determine whether code for certain features
- * should be compiled into guile.  The common prefix for all option macros
- * of this kind is "SCM_ENABLE_".  It is guaranteed that a macro named
- * SCM_ENABLE_XXX is defined to be either 0 or 1, i. e. there is no need to
- * test for the undefined case.  This allows to use these definitions
- * comfortably within code, as in the following example:
- *   #define FOO do { if (SCM_ENABLE_XXX) bar(); else baz(); } while (0)
- * Any sane compiler will remove the unused branch without any performance
- * penalty for the resulting code.
- *
- * Note:  Some SCM_ENABLE_XXX options are not settable at configure time.
- * To change the value of such options you will have to edit this header
- * file or give suitable options to make, like:
- *   make all CFLAGS="-DSCM_ENABLE_XXX=1 ..."
- */
-
-/* If SCM_ENABLE_DEPRECATED is set to 1, deprecated code will be included in
- * guile, as well as some functions to issue run-time warnings about uses of
- * deprecated functions.
- */
+/* If SCM_ENABLE_DEPRECATED is set to 1, deprecated code will be
+   included in Guile, as well as some functions to issue run-time
+   warnings about uses of deprecated functions.  */
 #ifndef SCM_ENABLE_DEPRECATED
 #define SCM_ENABLE_DEPRECATED 0
 #endif
 
 
 
-/* {Architecture and compiler properties}
- *
- * Guile as of today can only work on systems which fulfill at least the
- * following requirements:
- *
- * - scm_t_bits and SCM variables have at least 32 bits.
- *   Guile's type system is based on this assumption.
- *
- * - sizeof (scm_t_bits) >= sizeof (void*) and sizeof (SCM) >= sizeof (void*)
- *   Guile's type system is based on this assumption, since it must be
- *   possible to store pointers to cells on the heap in scm_t_bits and SCM
- *   variables.
- *
- * - sizeof (scm_t_bits) >= 4 and sizeof (scm_t_bits) is a power of 2.
- *   Guile's type system is based on this assumption.  In particular, it is
- *   assumed that cells, i. e. pairs of scm_t_bits variables, are eight
- *   character aligned.  This is because three bits of a scm_t_bits variable
- *   that is holding a pointer to a cell on the heap must be available for
- *   storing type data.
- *
- * - sizeof (scm_t_bits) <= sizeof (void*) and sizeof (SCM) <= sizeof (void*)
- *   In some parts of guile, scm_t_bits and SCM variables are passed to
- *   functions as void* arguments.  Together with the requirement above, this
- *   requires a one-to-one correspondence between the size of a void* and the
- *   sizes of scm_t_bits and SCM variables.
- *
- * - numbers are encoded using two's complement.
- *   The implementation of the bitwise scheme level operations is based on
- *   this assumption.
- *
- * - ... add more
- */
-
-#ifdef CHAR_BIT
-# define SCM_CHAR_BIT CHAR_BIT
-#else
-# define SCM_CHAR_BIT 8
-#endif
-
-#ifdef LONG_BIT
-# define SCM_LONG_BIT LONG_BIT
-#else
-# define SCM_LONG_BIT (SCM_SIZEOF_LONG * 8)
-#endif
+/* Guile as of today can only work on systems which fulfill at least the
+   following requirements:
+  
+   - scm_t_bits and SCM variables have at least 32 bits.
+     Guile's type system is based on this assumption.
+  
+   - sizeof (scm_t_bits) >= sizeof (void*) and sizeof (SCM) >= sizeof (void*)
+     Guile's type system is based on this assumption, since it must be
+     possible to store pointers to cells on the heap in scm_t_bits and
+     SCM variables.
+  
+   - sizeof (scm_t_bits) >= 4 and sizeof (scm_t_bits) is a power of 2.
+     Guile's type system is based on this assumption.  In particular, it
+     is assumed that cells, i. e. pairs of scm_t_bits variables, are
+     eight-byte aligned.  This is because three bits of a scm_t_bits
+     variable that is holding a pointer to a cell on the heap must be
+     available for storing type data.
+  
+   - sizeof (scm_t_bits) <= sizeof (void*) and sizeof (SCM) <= sizeof (void*)
+     In some parts of guile, scm_t_bits and SCM variables are passed to
+     functions as void* arguments.  Together with the requirement above,
+     this requires a one-to-one correspondence between the size of a
+     void* and the sizes of scm_t_bits and SCM variables.
+  
+   - numbers are encoded using two's complement.
+     The implementation of the bitwise Scheme-level operations is based on
+     this assumption.  */
 
 
 
@@ -297,47 +221,38 @@
    any arity.  However, these are equivalent to `(void)' in C++, are
    obsolescent as of C99, and trigger `strict-prototypes' GCC warnings
    (bug #23681).  */
-
 #ifdef BUILDING_LIBGUILE
 typedef SCM (* scm_t_subr) ();
 #else
 typedef void *scm_t_subr;
 #endif
 
-
-
 typedef struct scm_dynamic_state scm_t_dynamic_state;
+typedef struct scm_print_state scm_print_state;
+typedef struct scm_dynstack scm_t_dynstack;
+typedef scm_t_int32 scm_t_wchar;
 
 
 
 
-/* If stack is not longword aligned then
- */
-
-typedef long SCM_STACKITEM;
-
-/* Cast pointer through (void *) in order to avoid compiler warnings
-   when strict aliasing is enabled */
-#define SCM_STACK_PTR(ptr) ((SCM_STACKITEM *) (void *) (ptr))
-
-
-/* Handling thread-local storage (TLS).  */
-
-#ifdef SCM_HAVE_THREAD_STORAGE_CLASS
-# define SCM_THREAD_LOCAL __thread
+#ifdef CHAR_BIT
+# define SCM_CHAR_BIT CHAR_BIT
 #else
-# define SCM_THREAD_LOCAL
+# define SCM_CHAR_BIT 8
 #endif
 
-#endif  /* SCM___SCM_H */
-
+#ifdef LONG_BIT
+# define SCM_LONG_BIT LONG_BIT
+#else
+# define SCM_LONG_BIT (SCM_SIZEOF_LONG * 8)
+#endif
 
 
 
-/* Trivial type declarations and forward declarations.  */
-typedef struct scm_print_state scm_print_state;
-typedef struct scm_dynstack scm_t_dynstack;
-typedef scm_t_int32 scm_t_wchar;
+/* Cast pointer through (void *) in order to avoid compiler warnings
+   when strict aliasing is enabled */
+typedef long SCM_STACKITEM;
+#define SCM_STACK_PTR(ptr) ((SCM_STACKITEM *) (void *) (ptr))
 
 
-
+#endif  /* SCM___SCM_H */