From d464704f111d211c1f1ff9ef23ef1d755054be00 Mon Sep 17 00:00:00 2001 From: shyouhei Date: Wed, 15 Aug 2007 19:08:43 +0000 Subject: add tag v1_8_5_54 git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/tags/v1_8_5_54@12952 b2dd03c8-39d4-4d8f-98ff-823fe69b080e --- ruby_1_8_5/ext/dl/doc/dl.txt | 266 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 266 insertions(+) create mode 100644 ruby_1_8_5/ext/dl/doc/dl.txt (limited to 'ruby_1_8_5/ext/dl/doc/dl.txt') diff --git a/ruby_1_8_5/ext/dl/doc/dl.txt b/ruby_1_8_5/ext/dl/doc/dl.txt new file mode 100644 index 0000000000..893bd21d79 --- /dev/null +++ b/ruby_1_8_5/ext/dl/doc/dl.txt @@ -0,0 +1,266 @@ +=begin + += Ruby/DL + +Ruby/DL provides an interface to the dynamic linker such as dlopen() on UNIX +and LoadLibrary() on Windows. + += Building and Installing + + $ ruby extconf.rb # to create the Makefile + $ make # to build the library 'dl.so' + $ make libtest.so # to build the C library 'libtest.so' for the test script + $ make test # to run the test script + $ make install # to install the library + $ make clean # to remove the created files without Makefile + $ make distclean # to remove the all created files + += Using Ruby/DL + +We should usually use DL::Importable module provided by "dl/import.rb". +It has high-level functions to access library functions. We use +DL::Importable module to extend a module as follows: + + require "dl/import" + module LIBC + extend DL::Importable + end + +Now we can use methods dlload and extern in this module. We load the +libraries using dlload, and define wrapper methods to library functions +using extern respectively as follows: + + module LIBC + extend DL::Importable + dlload "libc.so.6","libm.so.6" + extern "int strlen(char*)" + end + # Note that we should not include the module LIBC from some reason. + +We can call the library function strlen() using LIBC.strlen. If the first +character of given function name is an uppercase, the first character of the +defined method name becomes lowercase. +We can also construct memory images of structures and unions using functions +struct and union which are defined in "dl/struct.rb" as follows: + + require "dl/import" + require "dl/struct" + module LIBC + extend DL::Importable + Timeval = struct [ # define timeval structure. + "long tv_sec", + "long tv_uses", + ] + end + val = LIBC::Timeval.malloc # allocate memory. + +Notice that the above example takes LIBC::Timeval.malloc to allocate memory, +rather than LIBC::Timeval.new. It is because DL::Timeval.new is for wrapping +an object, PtrData, which has already been created. + +We can define a callback using the module function "callback" as follows: + + module Foo + extend DL::Importable + def my_comp(str1,str2) + str1 <=> str2 + end + COMPARE = callback "int my_comp(char*,char*)" + end + +where Foo::COMPARE is a Symbol object which invokes the method "my_comp". + +DL::Importable module is very useful. However, we sometimes encounter a case +that we must directly use low-level functions such as dlsym(). In such case, +we would use DL module functions. They are described in next section. + += DL module + +Module DL consists of three classes, a few module functions and constants. +The class Symbol represents the symbol we can call. The class PtrData +indicates a memory block such as a pointer in C. An object instantiated from +the class Handle keeps a handle to opened library. + +== Constants + +* VERSION +* MAJOR_VERSION +* MINOR_VERSION +* PATCH_VERSION +* RTLD_GLOBAL +* RTLD_LAZY +* RTLD_NOW +* MAX_ARG +* MAX_CBARG +* MAX_CBENT + +== Functions + +* handle = dlopen(lib){|handle| ... } + * is quite equal to `Handle.new(lib)' + +* sym = set_callback(cbtype, entry){|args| ... } +* sym = set_callback(cbtype, entry, proc) + * makes entry-th pre-defined function to call the proc or given block. the + entry-th pre-defined function is specified by cbtype and entry. cbtype is a + prototype of the callback. see also the section `Type specifiers' about + cbtype. + +* sym = get_callback(cbtype, entry) + * returns the Proc object which is given by the above function + `set_callback'. + +* ptr = malloc(size, [free = nil]) + * allocates the size bytes, and returns the pointer as a PtrData object ptr. + +* ptr = strdup(str) + * returns a PtrData object ptr which represents the pointer to a new string + which is a duplicate of the string str. + +* size = sizeof(type) + * returns the size of type. `sizeof("C") + sizeof("L")' is not equal to + `sizeof("CL")'. the latter is assumed to returns the enough size of the + structure `struct foo { char c; long l; }', but the size may not equal to + `sizeof(foo)' of C. + +== Handle class + +* handle = Handle.new(lib){|handle| ... } + * opens a library lib and returns a Handle object handle. if a block is + given, the handle is automatically closed as the block ends. + +* Handle#close + * closes the handle opened by the above Handle.new(lib). + +* sym = Handle#sym(func, prototype = "0"), + sym = Handle#[func, prototype = nil] + + * obtains the pointer to a function called func and returns a Symbol object + or a DataPtr object. prototype is a string which consists of type + specifiers, it indicates the function's prototype. see also the section + `Type specifiers'. + +== Symbol class + +* sym = Symbol.new(addr, type = nil, name = nil) + * creates the Symbol object sym with the type type if type is not nil. addr + is the address where the function is allocated. If type is nil, it returns + a DataPtr object. + +* Symbol::char2type(char) + * takes a character char that represents a type and returns the type + specifier of the C language. + +* str = Symbol#proto() + * returns the function prototype. + +* str = Symbol#name() + * Returns the function name. + +* str = Symbol#cproto(), + str = Symbol#to_s() + * returns the prototype of the C language. + +* str = Symbol#inspect() + * returns the inspectable string. + +* r,rs = Symbol#call(arg1,arg2,...,argN), + r,rs = Symbol#[](arg1,arg2,...,argN) + * calls the function with parameters arg1, arg2, ..., argN. and the result + consists of the return value r and parameters rs. rs is an array. + +* ptr = Symbol#to_ptr + * returns the corresponding PtrData object ptr. + +== PtrData class + +* ptr = PtrData.new(addr, [size = 0, free = nil]) + * returns the PtrData object representing the pointer which indicates the + address addr. GC frees the memory using the free function. + +* PtrData#free=(sym) + * If you specify a symbol object sym, GC frees the memory using the function + represented by sym. + +* sym = PtrData#free + * returns a symbol object sym which is used when GC frees the memory. it + usually configured by `PtrData#free=' or `PtrData.new'. + +* size = PtrData#size, PtrData#size=(size) + * gets and sets allocated size of the memory. + +* ary = PtrData#to_a(type, [size]) + * returns an array of the type which specified with type. type must be one of + 'S','P','I','L','D' and 'F'. + +* str = PtrData#to_s([len]) + * returns a string which length is len. if len is omitted, the end of the + string is '\0'. + +* ptr = PtrData#ptr,+@ + * returns the pointed value as a PtrData object ptr. + +* ptr = PtrData#ref,-@ + * returns the reference as a PtrData object ptr. + +* ptr = PtrData#+ + * returns the PtrData object + +* ptr = PtrData#- + * returns the PtrData object + +* PtrData#struct!(type, *members) + * defines the data type to get access to a structure member with a symbol. + (see also PtrData#[]) + +* PtrData#union!(type, *members) + * defines the data type to get access to a union member with a symbol. (see + also PtrData#[]) + +* val = PtrData#[key], PtrData#[key, num = 0] + * if the key is a string or symbol, this method returns the value of the + structure/union member which has the type defined by PtrData# + {struct!,union!}. if the key is a integer value and this object represents + the pointer ptr, it returns the value of `(ptr + key).to_s(num)' + +* PtrData#[key,num]=val, PtrData#[key]=val + * if the key is a string or symbol, this method substitute the value of the + structure/union member with val. if the key is a integer value and val is a + string, this method copies num bytes of val to the memory area ptr using + memcpy(3). + +== Type specifiers + +the prototype consists of the following type specifiers, first element of +prototype represents the type of return value, and remaining elements represent +the type of each argument. + + C : char + c : char * + H : short + h : short * + I : int + i : int * + L : long + l : long * + F : float + f : float * + D : double + d : double * + S : const char * + s : char * + A : const type[] + a : type[] (allocates new memory space) + P : void * (same as 'p') + p : void * (same as 'P') + 0 : void function (this must be a first character of the prototype) + +the cbtype consists of type specifiers 0, C, I, H, L, F, D, S and P. +for example: + + DL.callback('IPP'){|ptr1,ptr2| + str1 = ptr1.ptr.to_s + str2 = ptr2.ptr.to_s + str1 <=> str2 + } +=end -- cgit v1.2.3