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Questions tagged [macros]

***DO NOT USE for VBA / MS-Office languages. Use [vba] instead.*** A macro is a rule or pattern that specifies how a certain input sequence (often a sequence of characters) should be mapped to an output sequence (also often a sequence of characters) according to a defined procedure.

A macro is a rule or pattern that specifies how a certain input sequence (often a sequence of characters) should be mapped to an output sequence (also often a sequence of characters) according to a defined procedure. The mapping process that instantiates (transforms) a macro into a specific output sequence is known as macro expansion.

Wikipedia Article for Macro

'Macros' created in VBA/MS-Office applications, while sharing the same name, are not the same concept as defined here. Questions relating to VBA should be tagged and the respective Office-Product, e.g. , . Please see the tag wiki entry page for more information regarding proper usage.

Similarly, questions relating to other macro programming languages should not use this tag.

13505 questions
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Are typedef and #define the same in c?

I wonder if typedef and #define are the same in c?
user188276
143
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8 answers

Where are the recorded macros stored in Notepad++?

I have recorded a macro that I want to share with my work colleague. In what location are these recorded macros saved, so that I can add it to his machine? If interested, the macro is for taking a list of values and adding quotes and comma so that…
heedfull
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What's the use of do while(0) when we define a macro?

Possible Duplicates: Do-While and if-else statements in C/C++ macros do { … } while (0) — what is it good for? I'm reading the linux kernel and I found many macros like this: #define INIT_LIST_HEAD(ptr) do { \ (ptr)->next = (ptr); (ptr)->prev…
amazingjxq
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3 answers

Constexpr vs macros

Where should I prefer using macros and where should I prefer constexpr? Aren't they basically the same? #define MAX_HEIGHT 720 vs constexpr unsigned int max_height = 720;
Tom Dorone
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How to pass macro definition from "make" command line arguments (-D) to C source code?

I usually pass macro definitions from "make command line" to a "makefile" using the option : -Dname=value. The definition is accessible inside the makefile. I also pass macro definitions from the "makefile" to the "source code" using the similar…
MohamedEzz
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16 answers

Is there a __CLASS__ macro in C++?

Is there a __CLASS__ macro in C++ which gives the class name similar to __FUNCTION__ macro which gives the function name
mortal
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136
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14 answers

Inline functions vs Preprocessor macros

How does an inline function differ from a preprocessor macro?
Subodh
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132
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15 answers

Optional Parameters with C++ Macros

Is there some way of getting optional parameters with C++ Macros? Some sort of overloading would be nice too.
Cenoc
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128
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4 answers

Swift: how to use PREPROCESSOR Flags (like `#if DEBUG`) to implement API keys?

In Objective-C it was sometimes useful to use static string constants to define alternate API keys (for example to differentiate between RELEASE and DEBUG keys for analytics packages, like MixPanel, Flurry or Crashlytics): #if DEBUG static NSString…
cleverbit
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128
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8 answers

Comma in C/C++ macro

Say we have a macro like this #define FOO(type,name) type name Which we could use like FOO(int, int_var); But not always as simply as that: FOO(std::map, map_var); // error: macro "FOO" passed 3 arguments, but takes just 2 Of course we…
PoP
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4 answers

How to identify platform/compiler from preprocessor macros?

I'm writing a cross-platform code, which should compile at linux, windows, Mac OS. On windows, I must support visual studio and mingw. There are some pieces of platform-specific code, which I should place in #ifdef .. #endif environment. For…
Arenim
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3 answers

Creating C macro with ## and __LINE__ (token concatenation with positioning macro)

I want to create a C macro that creates a function with a name based on the line number. I thought I could do something like (the real function would have statements within the braces): #define UNIQUE static void Unique_##__LINE__(void) {} Which I…
DD.
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Macro definition to determine big endian or little endian machine?

Is there a one line macro definition to determine the endianness of the machine? I am using the following code but converting it to macro would be too long: unsigned char test_endian( void ) { int test_var = 1; unsigned char *test_endian =…
manav m-n
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3 answers

What predefined macro can I use to detect clang?

I'm trying to detect the compiler used to compile my source code. I can easily find predefined macros to check for MSVC or GCC (see https://github.com/cpredef/predef for example), but I cannot find any macro to check for clang. Does someone know if…
Pierre Bourdon
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3 answers

Jinja2 inline comments

How can I put comments inside Jinja2 argument list declaration ? Everything I have tried gives an error: jinja2.exceptions.TemplateSyntaxError: unexpected char u'#' {{ Switch('var', [('1', 'foo'), # comment 1 ('2', 'bar'), ## comment…
kimstik
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