In memory, i, s, t and u are all placed next to one another at specific addresses. The effect of the violation can range from nothing at all to a complete system crash. You end up damaging the code or variables in another application. On other systems (Windows 3.1, the Mac), however, the system is not aware of what you are doing. On a system with protected memory spaces (UNIX, Windows 98/NT), this sort of statement will cause the system to terminate execution of the program. In other words, you are writing into memory that your program does not own. The location s is more than likely outside of your program's memory space.
You might make the following global declaration in a program: For example, a floating point variable consumes 4 contiguous bytes in memory. It can also group bytes together as it needs to to form larger variables, arrays, and structures. The computer can access any address in memory at any time (hence the name "random access memory"). Memory addresses act just like the indexes of a normal array. In this array, every memory location has its own address - the address of the first byte is 0, followed by 1, 2, 3, and so on. Memory can be thought of simply as an array of bytes. RAM holds the programs that your computer is currently running along with the data they are currently manipulating (their variables and data structures). For example, your computer might have 16 or 32 or 64 megabytes of RAM installed right now. If you have not read it already, now would be a good time to read How Bits and Bytes Work to fully understand bits, bytes and words.Īll computers have memory, also known as RAM ( random access memory). Because this is what the function has received and knows about it.The previous discussion becomes a little clearer if you understand how memory addresses work in a computer's hardware. When debugging the function printData() in Eclipse/CDT (shown below with the MCUXpresso IDE 10.2 which is based on Eclipse Oxygen, but it is pretty much the same in any Eclipse version I’m aware of), then the parameters are displayed as normal pointers. As with the code above, the function printData() receives two pointers which are actually pointers to arrays. Readers familiar with the C/C++ programming language know that pointers and arrays are kind of interchangeable: a pointer to an element can always be treated as a pointer to an array of elements.
Which then prints something like this to the console: int buf Data dump PrintData("int buf Data dump", intArray, sizeof(intArray)/sizeof(intArray)) Static void printData(const char *msg, const int *intBuf, size_t bufSize) For example the following function takes a message string and pointer to integer data which then is printed to the console: In the C programming language it is good practice to pass values by reference (using a pointer), especially for large set of data.
0 kommentar(er)
