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Questions tagged [variadic-macros]

Variadic macros are a feature of the C-preprocessor that permit a variable number of arguments to a macro. They were added in the 1999 revision of the C standard.

Variadic macros are a feature of the C-preprocessor that permit a variable number of arguments to a macro. They were added in the 1999 revision of the C standard.

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Passing template parameters into macros in MSVC

I am trying to compile C++ code in Visual Studio 2017 that was originally developed on Linux. The project as is compiles on Linux but not in VS. The errors come from trying to use a macro to compare template…
ddesentz
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VC Bug? Compiler Unable to Count __VA_ARGS__' Arguments

Microsoft Visual Studio Professional 2015 Version 14.0.25431.01 Update 3 issues errors when compiling the code below. Looks like a bug to me. Thank you. #include #define A( a, b, c, ... ) #__VA_ARGS__ #define B( ... )…
zdf
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Forward Variadic Argument List to ncurses printw function in c

This has been asked in several different flavors. Yet I can still not get it to work. Here is my function definition. void …
Matthew Hoggan
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Simplifying work with variadic functions / macros

I'm writing a bunch of functions like this: template <> Error SyntaxError(unsigned int line) { std::stringstream message; message << "SyntaxError: unfinished string (starting at line " << line << ")."; return…
user6245072
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How to write a macro in Rust to match any element in a set?

In C, I'm used to having: if (ELEM(value, a, b, c)) { ... } which is a macro with a variable number of arguments to avoid typing out if (value == a || value == b || value == c) { ... } A C example can be seen in Varargs `ELEM` macro for use with…
ideasman42
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How to define recursive variadic macros?

I am trying to convert boolean values, which represent bits of a signal bus, into an integer. I am using the following construct: #define B_TO_UINT1(b00) (((uint32_t) b00 << 0)) #define B_TO_UINT2(b01, ...) (((uint32_t) b01 << 1) |…
ysap
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Filtering via macros

I would like to implement a debug printing mechanism that allows both run-time and compile time filtering. Filtering is accomplished via a one-hot encoded mask. Run-time filtering is done by checking the mask within a function. If the level is not…
trialUnplugged
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Variadic macros with function overloading

I have a function: SendMsg(int x, string y, ...) { /*some code*/ } I have a macro: FOO(X, STRING, ...) SendMsg(X, STRING "%s %d", ##__VA_ARGS__, "xyz", 123) so I can have something like this: FOO(1000, "Note that line %d containing %d words is…
user2524261
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C variadic macro

I defined two variadic macros below for debug printing. #define MYTRACE(fmt, args...) printf("%s(): "fmt"\n", __func__, ##args) #define MYTRACE_ERR(err, fmt, args...) printf("[ERR] %s(): "fmt" err=%d\n", __func__, ##args, err) Second is the one who…
Ozawa Tomohiko
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C99 Macro Expansion for Struct Member Access

Is it possible to do a nullity check and an access in a macro? Eg: #define LOG(mystruct, severity, format, ...) ({ \ severity_t current = ERROR; \ if (mystruct) { \ current = mystruct->error_level; \ } \ if (severity >= current) { \ …
bge0
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C++ macro functions with "..." parameter

What does "..." parameter in macro function mean and what does it do? #define ABC(...) some Code Here I don't understand what does this "..." in parameter help with and when should I use them? I have tried goggling about it but all i get is info on…
Karani.pranay
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Number of arguments in macro definition

I have some templated function which has different number of arguments due to the template-type. This function is wrapped with macro definition. #define SomeTemplate(TemplateType, Arguments) someFunc(Arguments); Everything is okay…
Max Frai
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Need to fix my Variadic Macros

I want to use variadic macros but I get errors #define SERVER_RE_1(ServerFunction, Type1) \ { \ Type1 arg1; …
Ufx
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How can I check variadic argument __VA_ARGS__ validity?

I wanted to define a macro like - #define log(lognumber,...) logreport(lognumber,__VA_ARGS__) I wanted to check the exception case for __VA_ARGS__ those arguments user can pass when that user calls log() .please provide me exception case for…
user2230832
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Android - NDK - Variadic macro requiring 1+ args

I have the following macro in a logging library of mine : #define TRACE_E(__logCat,__format,...) \ do { \ ::dbg::LogCategory * const __catPtrVal = (::dbg::LogCategory *)(__logCat); \ if( NULL != __catPtrVal &&…
Virus721
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