68 lines
4.4 KiB
Factor
Executable File
68 lines
4.4 KiB
Factor
Executable File
! Copyright (C) 2009 Slava Pestov.
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! See http://factorcode.org/license.txt for BSD license.
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USING: accessors alien alien.syntax assocs help.markup
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help.syntax io.backend kernel namespaces ;
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IN: alien.libraries
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HELP: <library>
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{ $values
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{ "path" "a pathname string" } { "abi" "the ABI used by the library, either " { $snippet "cdecl" } " or " { $snippet "stdcall" } }
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{ "library" library } }
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{ $description "Opens a C library using the path and ABI parameters and outputs a library tuple." }
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{ $notes "User code should use " { $link add-library } " so that the opened library is added to a global hashtable, " { $link libraries } "." } ;
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HELP: libraries
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{ $description "A global hashtable that keeps a list of open libraries. Use the " { $link add-library } " word to construct a library and add it with a single call." } ;
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HELP: library
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{ $values { "name" "a string" } { "library" assoc } }
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{ $description "Looks up a library by its logical name. The library object is a hashtable with the following keys:"
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{ $list
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{ { $snippet "name" } " - the full path of the C library binary" }
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{ { $snippet "abi" } " - the ABI used by the library, either " { $snippet "cdecl" } " or " { $snippet "stdcall" } }
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{ { $snippet "dll" } " - an instance of the " { $link dll } " class; only set if the library is loaded" }
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}
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} ;
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HELP: dlopen ( path -- dll )
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{ $values { "path" "a pathname string" } { "dll" "a DLL handle" } }
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{ $description "Opens a native library and outputs a handle which may be passed to " { $link dlsym } " or " { $link dlclose } "." }
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{ $errors "Throws an error if the library could not be found, or if loading fails for some other reason." }
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{ $notes "This is the low-level facility used to implement " { $link load-library } ". Use the latter instead." } ;
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HELP: dlsym ( name dll -- alien )
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{ $values { "name" "a C symbol name" } { "dll" "a DLL handle" } { "alien" "an alien pointer" } }
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{ $description "Looks up a symbol in a native library. If " { $snippet "dll" } " is " { $link f } " looks for the symbol in the runtime executable." }
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{ $errors "Throws an error if the symbol could not be found." } ;
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HELP: dlclose ( dll -- )
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{ $values { "dll" "a DLL handle" } }
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{ $description "Closes a DLL handle created by " { $link dlopen } ". This word might not be implemented on all platforms." } ;
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HELP: load-library
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{ $values { "name" "a string" } { "dll" "a DLL handle" } }
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{ $description "Loads a library by logical name and outputs a handle which may be passed to " { $link dlsym } " or " { $link dlclose } ". If the library is already loaded, returns the existing handle." } ;
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HELP: add-library
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{ $values { "name" "a string" } { "path" "a string" } { "abi" "one of " { $snippet "\"cdecl\"" } " or " { $snippet "\"stdcall\"" } } }
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{ $description "Defines a new logical library named " { $snippet "name" } " located in the file system at " { $snippet "path" } "and the specified ABI." }
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{ $notes "Because the entire source file is parsed before top-level forms are executed, " { $link add-library } " cannot be used in the same file as " { $link POSTPONE: FUNCTION: } " definitions from that library. The " { $link add-library } " call will happen too late, after compilation, and the alien calls will not work."
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$nl
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"Instead, " { $link add-library } " calls must either be placed in different source files from those that use that library, or alternatively, " { $link "syntax-immediate" } " can be used to load the library before compilation." }
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{ $examples "Here is a typical usage of " { $link add-library } ":"
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{ $code
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"<< \"freetype\" {"
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" { [ os macosx? ] [ \"libfreetype.6.dylib\" \"cdecl\" add-library ] }"
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" { [ os windows? ] [ \"freetype6.dll\" \"cdecl\" add-library ] }"
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" [ drop ]"
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"} cond >>"
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}
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"Note the parse time evaluation with " { $link POSTPONE: << } "." } ;
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ARTICLE: "loading-libs" "Loading native libraries"
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"Before calling a C library, you must associate its path name on disk with a logical name which Factor uses to identify the library:"
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{ $subsection add-library }
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"Once a library has been defined, you can try loading it to see if the path name is correct:"
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{ $subsection load-library }
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"If the compiler cannot load a library, or cannot resolve a symbol in a library, a linkage error is reported using the compiler error mechanism (see " { $link "compiler-errors" } "). Once you install the right library, reload the source file containing the " { $link add-library } " form to force the compiler to try loading the library again." ;
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