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comparison man/internals/internals.texi @ 265:8efd647ea9ca r20-5b31

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Import from CVS: tag r20-5b31
author cvs
date Mon, 13 Aug 2007 10:25:37 +0200
parents 11cf20601dec
children c5d627a313b1
comparison
equal deleted inserted replaced
264:682d2a9d41a5 265:8efd647ea9ca
1735 If all args return nil, return nil. 1735 If all args return nil, return nil.
1736 */ 1736 */
1737 (args)) 1737 (args))
1738 @{ 1738 @{
1739 /* This function can GC */ 1739 /* This function can GC */
1740 REGISTER Lisp_Object val; 1740 Lisp_Object val = Qnil;
1741 Lisp_Object args_left;
1742 struct gcpro gcpro1; 1741 struct gcpro gcpro1;
1743 1742
1744 if (NILP (args)) 1743 GCPRO1 (args);
1745 return Qnil; 1744
1746 1745 while (!NILP (args))
1747 args_left = args;
1748 GCPRO1 (args_left);
1749
1750 do
1751 @{ 1746 @{
1752 val = Feval (Fcar (args_left)); 1747 val = Feval (XCAR (args));
1753 if (!NILP (val)) 1748 if (!NILP (val))
1754 break; 1749 break;
1755 args_left = Fcdr (args_left); 1750 args = XCDR (args);
1756 @} 1751 @}
1757 while (!NILP (args_left));
1758 1752
1759 UNGCPRO; 1753 UNGCPRO;
1760 return val; 1754 return val;
1761 @} 1755 @}
1762 @end group 1756 @end group
4069 speed of anything. 4063 speed of anything.
4070 4064
4071 @item 4065 @item
4072 The general rule to follow is that caller, not callee, @code{GCPRO}s. 4066 The general rule to follow is that caller, not callee, @code{GCPRO}s.
4073 That is, you should not have to explicitly @code{GCPRO} any Lisp objects 4067 That is, you should not have to explicitly @code{GCPRO} any Lisp objects
4074 that are passed in as parameters, but if you create any Lisp objects 4068 that are passed in as parameters.
4075 (remember, this happens in all sorts of circumstances, e.g. with 4069
4076 @code{Fcons()}, etc.), you are responsible for @code{GCPRO}ing the 4070 One exception from this rule is if you ever plan to change the parameter
4077 objects unless you are @emph{absolutely sure} that there's no 4071 value, and store a new object in it. In that case, you @emph{must}
4078 possibility that a garbage-collection can occur while you need to use 4072 @code{GCPRO} the parameter, because otherwise the new object will not be
4079 the object. Even then, consider @code{GCPRO}ing. 4073 protected.
4074
4075 So, if you create any Lisp objects (remember, this happens in all sorts
4076 of circumstances, e.g. with @code{Fcons()}, etc.), you are responsible
4077 for @code{GCPRO}ing them, unless you are @emph{absolutely sure} that
4078 there's no possibility that a garbage-collection can occur while you
4079 need to use the object. Even then, consider @code{GCPRO}ing.
4080 4080
4081 @item 4081 @item
4082 A garbage collection can occur whenever anything calls @code{Feval}, or 4082 A garbage collection can occur whenever anything calls @code{Feval}, or
4083 whenever a QUIT can occur where execution can continue past 4083 whenever a QUIT can occur where execution can continue past
4084 this. (Remember, this is almost anywhere.) 4084 this. (Remember, this is almost anywhere.)