c99

I was browsing through some documentation and questions/answers and saw it mentioned. I read a brief description, stating that it would be basically a promise from the programmer that the pointer won't be used to point somewhere else. Can anyone offer some realistic cases where its worth actually using this? Michael restrict says that the pointer is the only thing that accesses the underlying object. It eliminates the potential for pointer aliasing, enabling better optimization by the compiler. For instance, suppose I have a machine with specialized instructions that can multiply vectors of

I'm trying to set up a "gcc99" alias in Windows PowerShell which is equal to "gcc -std=C99 -pedantic -Wall". The idea is to use fewer keystrokes to ensure that GCC is running in c99 mode. (I've tried my best to adapt the guidelines in the following post to Windows PowerShell: Setting std=c99 flag in GCC ) When I try to compile after setting up such an alias (exhibit 1 below), I receive an error. As reference, I don't receive this error if I use the extended command to compile (exhibit 2 below). As a test, I tried setting gc99 as an alias for "gcc" (no additional values) and it worked fine

One does usually associate 'unmodifiable' with the term literal char* str = "Hello World!"; *str = 'B'; // Bus Error! However when using compound literals, I quickly discovered they are completely modifiable (and locking at the generated machine code, you see they are pushed on the stack): char* str = (char[]){"Hello World"}; *str = 'B'; // A-Okay! I'm compiling with clang-703.0.29 . Shouldn't those two examples generate the exact same machine code? Is a compound literal really a literal, if it's modifiable? EDIT: An even shorter example would be: "Hello World"[0] = 'B'; // Bus Error! (char[])

I generally want to avoid code like this: #include <stdio.h> int main(int argc, char *argv[]){ int n = 3; for (int n = 1; n <= 10; n++){ printf("%d\n", n); } printf("%d\n", n); } How can I find such usage of variables? That means, that in the same function a "more local" variable has the same name as a more global variable? C-Standard : C 99 Both gcc and clang support the -Wshadow flag which will warn about variables that shadow one another. For example the warning I receive from gcc for your code is the following: warning: declaration of ‘n’ shadows a previous local [-Wshadow] for (int n = 1;

I have written an app in C which expects two lines at input. First input tells how big an array of int will be and the second input contains values separated by space. For example, the following input 5 1 2 3 4 99 should create an array containing {1,2,3,4,99} What is the fastest way to do so? My problem is to read multiple numbers without looping through the whole string checking if it's space or a number? Thanks. int i, size; int *v; scanf("%d", &size); v = malloc(size * sizeof(int)); for(i=0; i < size; i++) scanf("%d", &v[i]); Remember to free(v) after you are done! Also, if for some reason

From The GNU C Programming Tutorial : The fgets ("file get string") function is similar to the gets function. This function is deprecated -- that means it is obsolete and it is strongly suggested you do not use it -- because it is dangerous. It is dangerous because if the input data contains a null character, you can't tell. Don't use fgets unless you know the data cannot contain a null. Don't use it to read files edited by the user because, if the user inserts a null character, you should either handle it properly or print a clear error message. Always use getline or getdelim instead of fgets