logo
down
shadow

C macro expansion of a function pointer based on for loop incrementor


C macro expansion of a function pointer based on for loop incrementor

By : miti
Date : November 29 2020, 09:01 AM
around this issue What you are trying to do is not possible with a macro because macros are expanded at compile time, well before the runtime and loops start running.
However, you can easily do this with a for loop on an array of function pointers:
code :
typedef int(*funcbase_t)(int);
funcbase_t fbases[] = {
    funcbase0, funcbase1, funcbase2, funcbase3, ...
};
for(int i = 0; i < 32; i++)
    fbases[i](i);


Share : facebook icon twitter icon
CPP: avoiding macro expansion of a macro function parameter

CPP: avoiding macro expansion of a macro function parameter


By : user1616593
Date : March 29 2020, 07:55 AM
wish helps you what I'd like to do (for logging purposes) is something like this: , I'm doing:
code :
#include <cstdio>

#define FOO 1
#define BAR 2

#define LOG_SIMPLE(ptr, lib, str) printf("%s\n", #lib);
#define LOG(ptr, lib, str) LOG_SIMPLE(ptr, ##lib, str)

int main()
{
  LOG_SIMPLE(0, FOO, "some error");
  LOG(0, BAR, "some other error");
}
FOO
BAR
#include <stdio.h>

#define FOO 1
#define BAR 2

#define LOG_SIMPLE(ptr, str, lib) printf("%s\n", #lib);
#define LOG(ptr, str, lib, ...) LOG_SIMPLE(ptr, str, lib##__VA_ARGS__)

int main()
{
  LOG_SIMPLE(0, "some error", FOO);
  LOG(0, "some other error", BAR);
  LOG(0, "some other error", FOO, BAR);
}
FOO
BAR
FOO2
FOO
BAR
FOOBAR
gnuplot macro expansion in bash here document when in for loop

gnuplot macro expansion in bash here document when in for loop


By : P.Copai
Date : March 29 2020, 07:55 AM
seems to work fine This was caused by a bug. From the answer to the bug report http://sourceforge.net/p/gnuplot/bugs/1264/
C++ macro function expansion based on the macro function arguments

C++ macro function expansion based on the macro function arguments


By : ompgupta
Date : March 29 2020, 07:55 AM
this will help I don't think you can do it solely with preprocessing directives, since the preprocessor doesn't really give you the necessary mechanisms to guide macro expansion based on the arguments to the macro.
That said, you can perpetrate some mildly ugly hacks that will work. Consider the following code:
code :
#include <iostream>

#define MYLOG_ERR  1
#define MYLOG_INFO 0

#define P(a,b) a##b

#define MYLOG(x,y) do { if (P(MYLOG_,x)) { std::cerr << y << std::endl; } } while (0)


int main(void)
{
    MYLOG(ERR, "err");
    MYLOG(INFO, "info");
}
Understanding loop macro expansion

Understanding loop macro expansion


By : Biomed92
Date : March 29 2020, 07:55 AM
it should still fix some issue list-head and list-tail are initially the same (in the eq sense). list-head is a cons which cdr is the list being collected. list-tail points to the last cons in the list (except initially, see below).
To add an element to the end of the list, replacd modifies the cdr of list-tail to add a new cons, and list-tail is updated to point to the new cons.
Incorrect expansion of a function-like macro

Incorrect expansion of a function-like macro


By : Allan James
Date : September 22 2020, 05:00 AM
this will help Function-like macro definitions can't have whitespace after the macro name
code :
#define ENTRY (a,b) (a[b-1])              // wrong
#define ENTRY(a,b) ((a)[(b)-1])               // correct
Related Posts Related Posts :
  • N Queens Puzzle - Where is the Backtracking in this solution?
  • how to build a simple lock (mutex) on nios II cpu
  • Epoll with edge triggered and oneshot only reports once
  • how to implement (PHP Function)array_map funciton in c?
  • Find a sum of two distinct numbers from the set, closest to the query number
  • Trouble with array in function
  • C, Piping messages to child processes not working. Why?
  • CreateThread() passing struct arguments weirdly
  • How to change a char to ASCII form?
  • Pipes, dup2 and exec()
  • I can't get this mean calculated, it just displays 0 all the time
  • Expected ' ' before '=' token in struct definition
  • How to implement a MATLAB lowpass filter in C
  • Convert hexidecimal char array to u8 array in C
  • Delete function in Binary Tree in C
  • Why (int)((unsigned int)((int)v)?
  • Creating a matrix in a structure
  • C Recursion runtime error
  • C: pointer to 2d array
  • How to free a pointer in a structure array?
  • gcc -O optimization: Help me understand the effect
  • Errors on code (state machine)
  • Does node equals node on a struct initializes the rest of the struct attributes?
  • C program to copy one string into other string without using library functions
  • Macro representing a pin on a microchip
  • C code workks in Mac (Darwin 13.4), but not in Linux (2.6.32)
  • How do I read this complex C declaration?
  • Reading a file with scanf and a do while loop
  • why is the recursion used in finding the factorial of a number?
  • Inverting array elements (bitwise) doesn't work
  • git blame-like annotation of source files with gcov
  • Error using pthread on Windows with Mingw
  • How to create a static library with a Makefile from C source code
  • Why are there two different ways of initializing a pointer in C
  • Program runs too slowly with large input - C
  • Dangling pointer example confusion
  • Why is this program running when input is 1?
  • Malloc() doesn't work + char array clear
  • Reading debug registers on linux
  • Socket Programming - Server content written to Client (write())
  • Incrementing a string in C
  • what does a[0] = addr & 0xff?
  • unexpected EOF while looking for matching `'' while using execve()
  • What's the purpose of stack pointer alignment in the prologue of main()
  • Time from startup in linux kernel
  • UNIX socket connection refused
  • How to programmatically set IP address on Windows 7 using C
  • programming a gpu without using any library like cuda or opencl?
  • C "printf" Different output in Linux and Mac
  • Bit rearrangement/manipulation in C
  • How to find occurences of a digit with 4 in it within 50?
  • Read string separated by comma
  • how to optimize the C code, when m is too big, it can't operation
  • GCC Error Infinite While Loop
  • Row-major vs Column-major confusion
  • Parsing memory mapped file C
  • going out of bounds in array of structs in C
  • fprintf in do while loop wrote only one line in file C
  • Reading and Writing to Files in C
  • Changable amount of scanned numbers per line (scanf)
  • shadow
    Privacy Policy - Terms - Contact Us © animezone.co