second keyboard for macros

Problem: There is a requirement in work: you need to make some judgments and substitutions in LD script using macro definitions like C-Define.Experiment:1: Theoretically *.c can be used, whether GCC/LD also support the direct use of the macro in LD script, the result:Arm-linux-ld:xxx.lds:2: Ignoring invalid character ' # ' in Expressionarm-linux-ld:xxx.lds:2: syntax errorPeople say Shui, it seems that LD and GCC are not face ah. Here is the cross-compilation of the ld,x86 is the same conclusion,

Pre-processing macros in C + +An example of a preprocessing macro:# define PRINT (Str,var) coutThe arguments in parentheses following the macro name are replaced by all code that follows the closing parenthesis. Whenever the macro is called, the preprocessor removes the name print and replaces the code, so the compiler does not report any error messages when using the macro name, and it does not do any type checking on the parameters.Another example:#

The following information is excerpted from the documentation for standard C + +.If these macros are added to the program's log, it will provide a good help for the developer in analyzing the problem.standard C + + version 1998The following macro names shall is defined by the implementation:__line__ the line number of the current source line (a decimal constant).__file__ the presumed name of the source FILE (a character string literal).__date__ the DA

:#ifdef _cplusplus#define Extern_c EXTERN "C"#else#define Extern_c EXTERN#endif#ifdef _cplusplusextern "C" {#endifExtern_c int func (int a, int b);#ifdef _cplusplus}#endif5, MFC provides some macros, you can use Afx_ext_class to replace __declspec (DLLexport), and modify the class name, thereby exporting the class, afx_api_export to modify the function, Afx_data_export to modify the variableAfx_class_import:__declspec (DLLexport)Afx_api_import:__decls

Macros inside parameters without parentheses error-prone, when used as far as possible parenthesesProgram 1:#include #define sqare(X) x*xint Main (){int n = ten;int m= Sqare (n);printf ("m=%d\n", m);return 0;}Results:m=100Please press any key to continue ...Analysis: There seems to be no problem, see the following two examplesProgram 2:#include #define sqare(X) x*xint Main (){int m = Sqare (1 + 3); //1+3*1+3=7printf ("m=%d\n", m);return 0;}Results

the value of the list on the varargs variable. Kwargs is the same as varargs, but only for the keyword parameter. All unused keyword parameters are stored in this special variable. Caller if a macro is called by a call tag, the caller is stored in the variable as a callable macro. Macros can also expose certain internal details. The following macro object properties are available: The name of the name macro. {{Input.name}} will print input. Arguments

Calculation of bit segment size and application of macros # include Calculation of the "C-language" bit segment size and the application of macros

As mentioned in the previous notes, the parent process can get to its terminating state either through the wait function or the WAITPID function, regardless of whether the child process terminates normally or terminates abnormally. However, the information obtained by the normal termination and the abnormal termination of the parent process is different, and the parent process receives the parameter of exit in the child process at normal termination, and the parent process receives the signal nu

follows:myprintf (TEMPLT);be converted to:fprintf (STDERR,TEMPLT);This will not generate a compilation error if the TEMPLT is valid.Incorrect nesting-misnestingThe definition of a macro does not necessarily have to have a complete, paired parenthesis, but it is best to avoid such use in order to avoid errors and improve readability.Problems caused by operator precedence-operator precedence problemSince macros are simply replacements, if the parameter

You cannot use SQL expressions in the Criteria column of a macro. Typically, the direct execution of a macro is just a test. You can either attach a macro to a form, report, or control to respond to an event, or create a custom menu command that executes a macro, after you make sure that the macro is designed correctly. If you want Microsoft Access to temporarily ignore an action, enter False as a condition. Temporarily ignoring the action helps you find the problem in the macro. If you want

Va_list is a group of macros that solve the argument problem in the C language he has so many members:1) va_list type variable:#ifdef _m_alphatypedef struct{char* A0; /*pointertofirsthomedintegerargument*/int offset; /*byteoffsetofnextparameter*/}va_list;#elsetypedef char* Va_list; #endif2) _intsizeof macro, gets the space length occupied by the type, the minimum occupancy length is an integer multiple of int: #define _INTSIZEOF (N) (sizeof (n) +sizeo

Debug macros for Linux C programmingIn the process of completing the project, it is unavoidable to debug, here I give you a I am using a debug macro. Nonsense not much to say, directly on the code.Implementation code/*************************************************************************> File name:debug.c> Author:answer> Mail: [email protected]> Created time:2015 July 23 Thursday 18:19 48 seconds ****************************************************

16.4.2 me the basic idea of this set of macros The main idea of this set of macros is: Use Word "endnote + cross-reference" to create an automated numbering system. In order to reduce duplication of work, written "macro", and made "button", so that "n-step operation, 1-click to solve." 16.4.3 inserts 1 new document numbers (cursor moved to "after text to insert document Number": Suggest you move to the 5

① Click the menu bar-view-macros-to view the macros. ② Pop-up Macro interface, enter the name of the macro, here to facilitate memory, we named to move one column to the left, and then click the Create button. ③ in the new appearance of the interface, the input code, that is, the program language, I have written, you can copy directly. application.screenupdating = False x = Selec

You can use a macro to define a function that has no return value. For example: Copy Code code as follows: #define PRINTMAX (A, b) \ do \ {\ int x = A, y = b; \ printf ("Max:%d\n", x > y x:y); \} while (0)// ... Printmax (3, 4); Such "functions" are essentially different from functions in real sense, because a macro is a compile-time behavior that replaces text only before it is compiled. In the Python source code, you can often see a macro definition similar to the follow

Preface Export_symbol macros are used after Linux-2.6, in the Linux-2.4 kernel, the default non-static functions and variables are automatically imported into the kernel space and are not marked with Export_symbol (). Then, after Linux-2.6, all symbols are not exported by default, so use Export_symbol () to mark them. the role of 1.export_symbol macros The functions or symbols defined within the Export_sym

The concept of macros is no stranger to me, but I never use macros, but I always use procedures (subroutines), because I think the macro will make the program longer, although it executes faster than the calling subroutine. So have been not too cold to the macro, until looking at the program of Lao Luo found a useful macro, it makes the program's writing more concise, intuitive, and beyond the concept of my

)) #_ = = #_ = # ' User/ignore-last-operanduser=> (Ignore-last-operand (+ 1 2 10)) 3and C's macro is a bit like, but C's macro is in the pre-compilation phase to do text replacement, or weak point. Unlike Lisp, you can use macros at run time. Check the returned list with MacroexpandIn the above example, the process of removing the last symbol, and then evaluating the remaining list, is actually passed.(+ 1 2), 3 (+ 1 2)To know the list before the f

One, the code length: the macro is completely replaced, inserted into the program to make the code longer;The function code is only present in one place and is used when it is called.Second, the implementation speed: macro faster, because in the pre-compilation phase has been completed;The function is slower because of the need to call and return (stack/stack) extra time.Third, operator priority: macros sometimes need less parentheses to cause the cal

A little knowledge of some of the macros in C language 1.# #和 #C language, # #表示把两个宏参数贴合在一起, that is,#define Call (x, y) x# #y, perform a call (x, y) result of XY, for example,int x=2,y=5;int xy=90;printf ("%d\n", call (x, y));//result is 90# #被称为连接符, used to concatenate two macro parameters into a single macro parameter.The function of a single # is to string the macro arguments that follow it, simply by substituting a double quotation mark around th