I understand that sizeof is an operator, which is evaluated at compile time to an integer constant. But it seem it can not be used in the #if preprocessor directive like: #if 4 == sizeof(int) typedef int Int32; #endif (cygwin-gcc 3.4.4 as well as Visual C++ 6.0 report compile errors) Why is such usage not allowed? ...
#include<stdio.h> #define TOTAL_ELEMENTS (sizeof(array) / sizeof(array[0])) int array[] = {23, 34, 12, 17, 204, 99, 16}; int main() { int d; for (d = -1; d <= (TOTAL_ELEMENTS - 2); d++) printf("%d\n", array[d + 1]); return 0; } Why is the for loop not run even once? ...
I'm sure there are sometimes good reasons for taking the sizeof() a #define in C, but I occasionally come across bugs where someone has taken the sizeof() a #define instead of the sizeof() a structure (and in my codebase I don't need to take the sizeof() a #define). For example (contrived, but hopefully illustrates the point): typedef ...
Sorry scratch my last post, it's way to late =S But basically I'm having problems sending out the buffer I created. Just need to know where I'm going wrong =( or if theres a better way. ------ Client Sending Username ------- int bufferSize = 32; char messageBuffer[bufferSize]; char* message; if (userName.size() > 8) { cout << "I...
I have two DLLs compiled separately, one is compiled from Visual Studio 2008 and one is a mex file compiled from matlab. Both DLLs have a header file which they include. when I take the sizeof() the struct in one DLL it returns 48, and in the other it returns 64. I've checked the /Zp switch and in both compilations it is set to /Zp8. Wha...
Why does the following code generate a compile error? Edit: My original code wasn't clear - I've split the code up into separate files... First.h class First { public: static const char* TEST[]; public: First(); }; First.cpp const char* First::TEST[] = {"1234", "5678"}; First::First() { uint32_t len = sizeof(TES...
Hi all, In the C++ code below, the templated Check function gives an output that is not what I would like: it's 1 instead of 3. I suspect that K is mapped to int*, not to int[3] (is that a type?). I would like it to give me the same output than the second (non templated) function, to which I explicitly give the size of the array... Sh...
This question is about C++ I always thought that name of an array in C++ is only a pointer, so I thought that int ar[10]; cout << sizeof(ar); will give me the same as sizeof(int *). But it gives 40 - so it is real size of whole array. It also gives 40 when array size is given by variable: int n = 10; int ar[n] I want to copy a cla...
Possible Duplicate: Why isnt sizeof for a struct equal to the sum of sizeof of each member? Why is the sizeof(); of this structure 16 bytes? I'm compiling in g++. struct bitmapfileheader { unsigned short bfType; unsigned int bfSize; unsigned short bfReserved1; unsigned short bfReserved2; unsigne...
Let's say that I want to get the size in bytes or in chars for the name field from: struct record { int id; TCHAR name [50]; }; sizeof(record.name) does not work. ...
In C I have an array of structs defined like: struct D { char *a; char *b; char *c; }; static struct D a[] = { { "1a", "1b", "1c" }, { "2a", "2b", "2c" } }; I would like to determine the number of elements in the array, but sizeof(a) returns an incorrect resu...
Hey, I have a a struct defined thusly: typedef struct _CONFIGURATION_DATA { BYTE configurationIndicator; ULONG32 baudRate; BYTE stopBits; BYTE parity; BYTE wordLength; BYTE flowControl; BYTE padding; } CONFIGURATION_DATA; Now, by my reckoning, that struct is 10 bytes long. However, sizeof reports that it ...
On Linux systems (either 32- or 64-bit), what is the size of pid_t, uid_t, and gid_t? ...
why isn't the size of an array sent as a parameter the same as within main? #include <stdio.h> void PrintSize(int p_someArray[10]); int main () { int myArray[10]; printf("%d\n", sizeof(myArray)); /* as expected 40 */ PrintSize(myArray);/* prints 4 not 40 */ } void PrintSize(int p_someArray[10]){ printf("%d\n", sizeof(...
I have two tasks for an assignment, one return the number of bits in type int on any machine. I thought I would write my function like so: int CountIntBitsF() { int x = sizeof(int) / 8; return x; } Does that look right? The second part is to return the number of any bits of any data type with a macro, and the macro can be ...
I'm trying to write a bit rotator function and I'm trying to get more clarification the sizeof operator. Since I don't know what type of numerical object I need to rotate, I assume I need to use the sizeof operator for unsigned rotator(unsigned object, int count) this function prototype where object is the object to be rotated and c...
I'm having a look at Go, which looks quite promising. I am trying to figure out how to get the size of a go struct, for example something like type Coord3d struct { X, Y, Z int64 } Of course I know that it's 24 bytes, but I'd like to know it programmatically.. Do you have any ideas how to do this ? ...
I know that sizeof is a compile-time calculation, but this seems odd to me: The compiler can take either a type name, or an expression (from which it deduces the type). But how do you identify a type within a class? It seems the only way is to pass an expression, which seems pretty clunky. struct X { int x; }; int main() { // ret...
I have a .c file with the following uint8_t buffer[32] I have a .S file where I want to do the following cpi r29, buffer+sizeof(buffer) The second argument for cpi muste be an immediate value, not a location. But unfortunately sizeof() is a C operator. Both files are compiled to separate object files and linked together afterward...
sizeof(void*) and sizeof(function_type_ptr*) equality Must sizeof(void*) and sizeof(function_type_ptr*) be equal? Is it required by C (C90, C99) standard? function_type_ptr is pointer to function. This question is about standard requirements, not your own opinion. Please, give links, section numbers and quotations from standards ...