0.9.14.30:

[sbcl.git] / doc / manual / ffi.texinfo

diff --git a/doc/manual/ffi.texinfo b/doc/manual/ffi.texinfo
index 0b1f2c0..f8ffb73 100644 (file)
--- a/doc/manual/ffi.texinfo
+++ b/doc/manual/ffi.texinfo
@@ -3,7 +3,7 @@
 @chapter Foreign Function Interface
 
 This chapter describes SBCL's interface to C programs and
-libraries (and, since C interfaces are a sort of @emph{ingua
+libraries (and, since C interfaces are a sort of @emph{lingua
 franca} of the Unix world, to other programs and libraries in
 general.)
 
@@ -196,8 +196,10 @@ variables. Dynamic arrays can only be allocated using
 The foreign type specifier @code{(sb-alien:struct @var{name} &rest
 @var{fields})} describes a structure type with the specified
 @var{name} and @var{fields}. Fields are allocated at the same offsets
-used by the implementation's C compiler. If @var{name} is @code{nil}
-then the structure is anonymous.
+used by the implementation's C compiler, as guessed by the SBCL
+internals. An optional @code{:alignment} keyword argument can be
+specified for each field to explicitly control the alignment of a
+field. If @var{name} is @code{nil} then the structure is anonymous.
 
 If a named foreign @code{struct} specifier is passed to
 @code{define-alien-type} or @code{with-alien}, then this defines,
@@ -216,9 +218,9 @@ determine which field is active from context.
 @item
 The foreign type specifier @code{(sb-alien:enum @var{name} &rest
 @var{specs})} describes an enumeration type that maps between integer
-values and keywords. If @var{name} is @code{nil}, then the type is
+values and symbols. If @var{name} is @code{nil}, then the type is
 anonymous.  Each element of the @var{specs} list is either a Lisp
-keyword, or a list @code{(@var{keyword} @var{value})}.  @var{value} is
+symbol, or a list @code{(@var{symbol} @var{value})}.  @var{value} is
 an integer. If @var{value} is not supplied, then it defaults to one
 greater than the value for the preceding spec (or to zero if it is the
 first spec).
@@ -282,12 +284,14 @@ return zero values.
 
 @item
 The foreign type specifier @code{sb-alien:c-string} is similar to
-@code{(* char)}, but is interpreted as a null-terminated string, and
-is automatically converted into a Lisp string when accessed; or if the
+@code{(* char)}, but is interpreted as a null-terminated string, and is
+automatically converted into a Lisp string when accessed; or if the
 pointer is C @code{NULL} or @code{0}, then accessing it gives Lisp
-@code{nil}.  Lisp strings are stored with a trailing NUL
-termination, so no copying (either by the user or the implementation)
-is necessary when passing them to foreign code.
+@code{nil}.  Lisp strings of type @code{base-string} are stored with a
+trailing NUL termination, so no copying (either by the user or the
+implementation) is necessary when passing them to foreign code; strings
+of type @code{(simple-array character (*))} are copied by the
+implementation as required.
 
 Assigning a Lisp string to a @code{c-string} structure field or
 variable stores the contents of the string to the memory already
@@ -355,7 +359,7 @@ array type. @code{deref} can be set with @code{setf} to assign a new
 value.
 @end defun
 
-@defun sb-alien:slot @var{struct-or-union} &rest @var{slot-names}
+@defun sb-alien:slot @var{struct-or-union} @var{slot-name}
 @findex slot
 
 The @code{sb-alien:slot} function extracts the value of the slot named
@@ -1119,7 +1123,7 @@ struct c_struct *c_function (i, s, r, a)
   printf("s = %s\n", s);
   printf("r->x = %d\n", r->x);
   printf("r->s = %s\n", r->s);
-  for (j = 0; j < 10; j++) printf("a[%d] = %d.\n", j, a[j]);
+  for (j = 0; j < 10; j++) printf("a[%d] = %d.\n", j, a[j]);
   r2 = (struct c_struct *) malloc (sizeof(struct c_struct));
   r2->x = i + 5;
   r2->s = "a C string";
@@ -1182,16 +1186,15 @@ routine, e.g.: @samp{cc -c test.c && ld -shared -o test.so test.o} (In
 order to enable incremental loading with some linkers, you may need to
 say @samp{cc -G 0 -c test.c})
 
-Once the C code has been compiled, you can start up Lisp and load it
-in: @samp{sbcl} Lisp should start up with its normal prompt.
+Once the C code has been compiled, you can start up Lisp and load it in:
+@samp{sbcl}.  Lisp should start up with its normal prompt.
 
 Within Lisp, compile the Lisp file. (This step can be done
 separately. You don't have to recompile every time.)
 @samp{(compile-file "test.lisp")}
 
 Within Lisp, load the foreign object file to define the necessary
-symbols: @samp{(load-shared-object "test.so")}.  This must be done
-before loading any code that refers to these symbols.
+symbols: @samp{(load-shared-object "test.so")}. 
 
 Now you can load the compiled Lisp (``fasl'') file into Lisp:
 @samp{(load "test.fasl")}