Another newbie question; Is it considered bad taste to use a lot of global variables in C ? I'm guessing the answer is probably yes, on the other hand, using main or some other function as a "base-function" to store pointers/values with global scope creates a whole mess with pointers to pointers etc... Any thoughts? ...
How to trigger C-preprocessor error about missing definition at #if? I'm using LLVM/Clang/Xcode. This code works. #define AAAAA 1 #if AAAAA #endif And I expected this code will be an error for undefined symbol. //#define AAAAA 1 Removed definition. #if AAAAA #endif But it did not. Is this standard/regular behavior? And is ther...
My code is pasted below.When I run this program,it keeps on calculating.I am using the old Turbo C++ compiler.How much time should such a program take to execute?I waited about 5 minutes but there wasn't any output. /*The sum of the primes below 10 is 2 + 3 + 5 + 7 = 17. Find the sum of all the primes below two million. */ #include<std...
AFAIK, PKCS#5 is used for hashing passwords. I could not find an example to explain how to use openssl to make a client for hashing the passwords. ...
How can I query if a service (dnsmasq) is running, in C? ...
Is there any downside to using typedef char bool; enum boolean { false, true }; in C to provide a semantic boolean type? ...
here a a piece of code that is supposed to loop over and over until the user inputs a number between 0 and 15 int input; do { printf("Enter a number => "); scanf("%d",&input); printf("\n %d \n",input); } while (!(input>0 && input <15)); However ...
I have a C function double* foofunc() {...} I don't know how to declare the interface in Fortran to call to this C function. The second question is: if this pointer is supposed to be pointing to GPU device memory. How could I define that in the Fortran interface, i.e. do I need to use DEVICE attribute. Thanks, T. Edit: Use any featu...
#include<stdio.h> int main() { char *p="mystring"; return 0; } String literal "mystring", where will be stored( in which segment) ? I am assuming that address of "mystring" is stored in 'p','p' will be in data segment and "mystring" will be stored in code segment. If my assumption is write can i say 'p' is a far pointer ? Ple...
So i have struct node { int number; struct node *next; struct deck{ int number; struct deck *next; }; }; I want to create a 2D linked list. How can i initialize something like this? Thanks. ...
Can we pass arguments of different datatypes to same variadic function at the same time? ...
I'm starting to build a real-time raytracer for iOS. I'm new to this raytracing thing, all I've done so far is write a rudimentary one in ObjC. It seems to me that a C-based raytracer is going to be faster than one written in ObjC, but the ObjC one will be far simpler, as object hierarchies come in very handy. Speed is very important,...
Declaring a variable register is a suggestion to the compiler that particular automatic variable should be allocated to CPU register, if possible. But how the compiler decides when to put the register variable to CPU register? Which algorithm/mechanism it uses to decide? Thanks, Naveen ...
I wrote a simple Perl script which will run in while loop and exit whenever any signal is send to this Perl script. I wrote a c program which creates a thread using the pthread_create() and in its start routine, it's using popen to execute that Perl script: popen("/usr/bin/perl myprog.pl"); I am using the sigtrap in the Perl script to...
How can I disable vertical scaling in GTK+? My program, which is currently only several controls in a few hbox objects stacked vertically in a vbox, stretches vertically when I increase the size of the window. I don't want this to occur. ...
why is sizeof void pointer 2 ? ...
In Win32 programming a handful of POD structs is used. Those structs often need to be zeroed out before usage. This can be done by calling memset()/ZeroMemory() STRUCT theStruct; ZeroMemory( &theStruct, sizeof( theStruct ) ); or by value initialization: STRUCT theStruct = {}; Although the two variants above are not equivalent in g...
I'd like to try to make a user-space device driver using libusb on Mac, but I'm confused where to start. In the SDK installer (which I got from http://www.ellert.se/twain-sane) it said something about examples which I couldn't find anywhere on my computer. Could anyone please describe how do I set up libusb for development on OS X? May ...
In GTK+ calls, arguments should (but don't have to) be casted from GtkWidget to the most specific class needed by the function before passing the argument. For example, sometimes I see some_call(GTK_WINDOW(window)); while other times, I see some_call((GtkWindow *) window); What's the difference? ...
Hello, in the following code when ran will produce a Segmentation Fault, due to a FILE* being passed to fclose which contains no address (NULL). I'm wondering why this is happening, the FILE* isn't being used what so over. The FILE* is named urandom and is passed to fclose in the main function. Thanks #include <stdio.h> #include <stdli...