*** empty log message ***

[bpt/guile.git] / libguile / __scm.h

diff --git a/libguile/__scm.h b/libguile/__scm.h
index 395cede..6ab774c 100644 (file)
--- a/libguile/__scm.h
+++ b/libguile/__scm.h
@@ -353,6 +353,42 @@
 # define SCM_CHAR_CODE_LIMIT 256L
 #endif
 
+#define SCM_I_UTYPE_MAX(type)      ((type)-1)
+#define SCM_I_TYPE_MAX(type,umax)  ((type)((umax)/2))
+#define SCM_I_TYPE_MIN(type,umax)  (-((type)((umax)/2))-1)
+
+#define SCM_T_UINT8_MAX   SCM_I_UTYPE_MAX(scm_t_uint8)
+#define SCM_T_INT8_MIN    SCM_I_TYPE_MIN(scm_t_int8,SCM_T_UINT8_MAX)
+#define SCM_T_INT8_MAX    SCM_I_TYPE_MAX(scm_t_int8,SCM_T_UINT8_MAX)
+
+#define SCM_T_UINT16_MAX  SCM_I_UTYPE_MAX(scm_t_uint16)
+#define SCM_T_INT16_MIN   SCM_I_TYPE_MIN(scm_t_int16,SCM_T_UINT16_MAX)
+#define SCM_T_INT16_MAX   SCM_I_TYPE_MAX(scm_t_int16,SCM_T_UINT16_MAX)
+
+#define SCM_T_UINT32_MAX  SCM_I_UTYPE_MAX(scm_t_uint32)
+#define SCM_T_INT32_MIN   SCM_I_TYPE_MIN(scm_t_int32,SCM_T_UINT32_MAX)
+#define SCM_T_INT32_MAX   SCM_I_TYPE_MAX(scm_t_int32,SCM_T_UINT32_MAX)
+
+#if SCM_HAVE_T_INT64
+#define SCM_T_UINT64_MAX  SCM_I_UTYPE_MAX(scm_t_uint64)
+#define SCM_T_INT64_MIN   SCM_I_TYPE_MIN(scm_t_int64,SCM_T_UINT64_MAX)
+#define SCM_T_INT64_MAX   SCM_I_TYPE_MAX(scm_t_int64,SCM_T_UINT64_MAX)
+#endif
+
+#if SCM_SIZEOF_LONG_LONG
+#define SCM_I_ULLONG_MAX  SCM_I_UTYPE_MAX(unsigned long long)
+#define SCM_I_LLONG_MIN   SCM_I_TYPE_MIN(long long,SCM_I_ULLONG_MAX)
+#define SCM_I_LLONG_MAX   SCM_I_TYPE_MAX(long long,SCM_I_ULLONG_MAX)
+#endif
+
+#define SCM_T_UINTMAX_MAX SCM_I_UTYPE_MAX(scm_t_uintmax)
+#define SCM_T_INTMAX_MIN  SCM_I_TYPE_MIN(scm_t_intmax,SCM_T_UINTMAX_MAX)
+#define SCM_T_INTMAX_MAX  SCM_I_TYPE_MAX(scm_t_intmax,SCM_T_UINTMAX_MAX)
+
+#define SCM_I_SIZE_MAX    SCM_I_UTYPE_MAX(size_t)
+#define SCM_I_SSIZE_MIN   SCM_I_TYPE_MIN(ssize_t,SCM_I_SIZE_MAX)
+#define SCM_I_SSIZE_MAX   SCM_I_TYPE_MAX(ssize_t,SCM_I_SIZE_MAX)
+
 \f
 
 #include "libguile/tags.h"
@@ -446,6 +482,32 @@ do { \
 #define SCM_FENCE
 #endif
 
+/* In the old days, SCM_DEFER_INTS stopped signal handlers from running,
+   since in those days the handler directly ran scheme code, and that had to
+   be avoided when the heap was not in a consistent state etc.  And since
+   the scheme code could do a stack swapping new continuation etc, signals
+   had to be deferred around various C library functions which were not safe
+   or not known to be safe to swap away, which was a lot of stuff.
+
+   These days signals are implemented with asyncs and don't directly run
+   scheme code in the handler, but hold it until an SCM_TICK etc where it
+   will be safe.  This means interrupt protection is not needed and
+   SCM_DEFER_INTS / SCM_ALLOW_INTS is something of an anachronism.
+
+   What past SCM_DEFER_INTS usage also did though was indicate code that was
+   not reentrant, ie. could not be reentered by signal handler code.  The
+   present definitions are a mutex lock, affording that reentrancy
+   protection against the new guile 1.8 free-running posix threads.
+
+   One big problem with the present defintions though is that code which
+   throws an error from within a DEFER/ALLOW region will leave the
+   defer_mutex locked and hence hang other threads that attempt to enter a
+   similar DEFER/ALLOW region.
+
+   The plan is to migrate reentrancy protection to an explicit mutex
+   (private or global, with unwind where necessary), and remove the
+   remaining DEFER/ALLOWs.  */
+
 #define SCM_DEFER_INTS scm_rec_mutex_lock (&scm_i_defer_mutex);
 
 #define SCM_ALLOW_INTS scm_rec_mutex_unlock (&scm_i_defer_mutex);
@@ -563,7 +625,7 @@ SCM_API SCM scm_apply_generic (SCM gf, SCM args);
          ? scm_apply_generic ((gf), (args))                              \
          : (scm_wrong_type_arg ((subr), (pos),                           \
                                 scm_list_ref ((args),                    \
-                                              SCM_MAKINUM ((pos) - 1))), \
+                                              scm_from_int ((pos) - 1))), \
             SCM_UNSPECIFIED))
 #define SCM_GASSERTn(cond, gf, args, pos, subr) \
   if (!(cond)) SCM_WTA_DISPATCH_n((gf), (args), (pos), (subr))