4288c6c2c7
punctuations outside of the form, as it does with quote punctuations.
So things like this
#, @foo{...}
that required the space to make the @foo read as a scribble form are
now better written as
@#,foo{...}
This changes all such occurrences. (In case you see this change in
your files and are worried that there might be changes: I mechanically
verified that the result of `read'ing the modified files is identical
to the previous version.)
svn: r15111
35 lines
1.6 KiB
Racket
35 lines
1.6 KiB
Racket
#lang scribble/doc
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@(require "utils.ss")
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@title[#:tag "intro"]{Overview}
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Although using the FFI requires writing no new C code, it provides
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very little insulation against the issues that C programmer faces
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related to safety and memory management. An FFI programmer must be
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particularly aware of memory management issues for data that spans the
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Scheme--C divide. Thus, this manual relies in many ways on the
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information in @|InsideMzScheme|, which defines how PLT Scheme
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interacts with C APIs in general.
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Since using the FFI entails many safety concerns that Scheme
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programmers can normally ignore, merely importing
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@schememodname[scheme/foreign] with @scheme[(require scheme/foreign)]
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does not import all of the FFI functionality. Only safe functionality
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is immediately imported. For example, @scheme[ptr-equal?] can never
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cause memory corruption or an invalid memory access, so it is
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immediately available on import.
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Use @scheme[(@#,indexed-scheme[unsafe!])] at the top-level of a
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module that imports @schememodname[scheme/foreign] to make unsafe
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features accessible. (For additional safety, the @scheme[unsafe!] is
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itself protected; see @secref[#:doc '(lib
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"scribblings/reference/reference.scrbl") "modprotect"].) Using this
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macro should be considered as a declaration that your code is itself
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unsafe, therefore can lead to serious problems in case of bugs: it is
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your responsibility to provide a safe interface. Bindings that become
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available only via @scheme[unsafe!] are documented in this manual in
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sections with titles starting ``Unsafe.''
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For examples of common FFI usage patterns, see the defined interfaces
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in the @filepath{ffi} collection.
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