0.9.7.2:

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

diff --git a/doc/manual/ffi.texinfo b/doc/manual/ffi.texinfo
index c8bc8d5..73871eb 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,
@@ -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
@@ -1182,8 +1186,8 @@ 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.)