mirror of https://github.com/acidanthera/audk.git
147 lines
6.0 KiB
C
147 lines
6.0 KiB
C
/** @file
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This header, <stdarg.h>, declares type va_list and defines macros: va_start, va_arg, va_end;
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for advancing through a list of arguments whose number and types are not known to the
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called function when it is translated.
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A function may be called with a variable number of arguments of varying types.
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The rightmost argument plays a special role in the access mechanism, and will
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be designated paramN in this and subsequent descriptions.
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The type va_list is a type suitable for holding information needed by the
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macros va_start, va_arg, and va_end. If access to the varying arguments
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is desired, the called function shall declare an object (referred to as ap
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in these descriptions) having type va_list. The object ap may be passed as
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an argument to another function; if the receiving function invokes the va_arg macro
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with parameter ap, the value of ap in the calling function becomes indeterminate
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and must be passed to the va_end macro prior to any further reference to ap.
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The va_start and va_arg macros must be implemented as macros, not as actual
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functions. The va_start and va_end macros must be invoked in the
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function accepting a varying number of arguments, if access to the varying
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arguments is desired.
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Copyright (c) 2010 - 2012, Intel Corporation. All rights reserved.<BR>
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This program and the accompanying materials are licensed and made available under
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the terms and conditions of the BSD License that accompanies this distribution.
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The full text of the license may be found at
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http://opensource.org/licenses/bsd-license.
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THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
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WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
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**/
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#ifndef _STDARG_H
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#define _STDARG_H
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#include <sys/EfiCdefs.h>
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/** @{
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The type va_list is a type suitable for holding information needed by the
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macros va_start, va_arg, and va_end.
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Depending upon compiler or CPU architecture, different definitions are required.
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**/
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#if defined(__GNUC__)
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typedef __builtin_va_list va_list;
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#else
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#define va_list VA_LIST
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#endif
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/*@}*/
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/** @{
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The va_start macro must be invoked before any access to the unnamed arguments.
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The va_start macro initializes ap for subsequent use by va_arg and va_end.
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Synopsys: void va_start(va_list ap, paramN);
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@param ap An object of type va_list that is to be initialized such
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that subsequent successive invocations of va_arg will
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return the values of the parameters following paramN.
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@param paramN The parameter paramN is the identifier of the rightmost
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parameter in the variable parameter list in the function
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definition (the one just before the ,...). If the
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parameter parmN is declared with the register storage
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class, with a function of array type, or with a type that
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is not compatible with the type that results after
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application of the default argument promotions, the
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behavior is undefined.
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**/
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#if defined(__GNUC__)
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#define va_start __builtin_va_start
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#else
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#define va_start VA_START
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#endif
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/*@}*/
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/** @{
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The va_arg macro expands to an expression that has the type and value of
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the next argument in the call. The parameter ap shall be the same as the
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va_list ap initialized by va_start. Each invocation of va_arg modifies ap
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so that the values of successive arguments are returned in turn. The
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parameter type is a type name specified such that the type of a pointer to
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an object that has the specified type can be obtained simply by postfixing
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a * to type. If there is no actual next argument, or if type is not
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compatible with the type of the actual next argument (as promoted
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according to the default argument promotions), the behavior is undefined.
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Synopsys: type va_arg(va_list ap, type);
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@param ap An object of type va_list that was initialized by a prior
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invocation of va_start.
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@param type A type name specifying the type of the parameter to be retrieved.
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@return The first invocation of the va_arg macro after that of the
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va_start macro returns the value of the argument after that
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specified by paramN. Successive invocations return the values
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of the remaining arguments in succession.
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**/
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#if defined(__GNUC__)
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#define va_arg __builtin_va_arg
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#else
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#define va_arg VA_ARG
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#endif
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/*@}*/
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/** @{
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The va_end macro facillitates a normal return from the function whose
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variable argument list was referred to by the expansion of va_start that
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initialized the va_list ap.
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Synopsys: void va_end(va_list ap);
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The va_end macro may modify ap so that it is no longer usable (without an
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intervening invocation of va_start). If there is no corresponding
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invocation of the va_start macro, or if the va_end macro is not invoked
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before the return, the behavior is undefined.
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@param ap An object of type va_list, initialized by a prior
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invocation of va_start, that will no longer be referenced.
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**/
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#if defined(__GNUC__)
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#define va_end __builtin_va_end
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#else
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#define va_end VA_END
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#endif
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/*@}*/
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/** @{
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For BSD compatibility.
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**/
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#if defined(__GNUC__)
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#define va_copy __builtin_va_copy
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#else
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#define va_copy(s,d) (s) = (d)
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#endif
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/*@}*/
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/** Provide a generic version of the compiler-dependent __va_copy macro.
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Some software, such as Python 2.7.2, relies upon the existence of __va_copy.
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If this macro is not defined, it just assigns one va_list item to another.
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This breaks for compiler environments that define va_list as an array or structure.
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**/
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#ifndef __va_copy
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#define __va_copy va_copy
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#endif
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#endif /* _STDARG_H */
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