# structure-packing

##### 包含位域的结构的大小[重复](size of a structure containing bit fields [duplicate])

2021-11-25 13:27:52    分类:技术分享    c++   c   sizeof   bit-fields   structure-packing

##### size of a structure containing bit fields [duplicate]

This question already has answers here: Closed 9 years ago. Possible Duplicate: Why isn't sizeof for a struct equal to the sum of sizeof of each member? I was trying to understand the concept of bit fields. But I am not able to find why the size of the following structure in CASE III is coming out as 8 bytes. CASE I: struct B { unsigned char c; // +8 bits } b; sizeof(b); // Output: 1 (because unsigned char takes 1 byte on my system) CASE II: struct B { unsigned b: 1; } b; sizeof(b); // Output: 4 (because unsigned takes 4 bytes on my system) CASE III: struct B { unsigned char c; // +8 bits

2021-11-20 10:06:43    分类:问答    c++   c   sizeof   bit-fields   structure-packing

##### _int64 位域(_int64 bit field)

2021-10-31 19:43:30    分类:技术分享    c   struct   bit-fields   int64   structure-packing

##### _int64 bit field

I need to use a 6-byte (48-bit) bitfield in a structure that I can use as unsigned integer for comparison etc. Something along the following: pack (1) struct my_struct { _int64 var1:48; } s; if (s.var >= 0xaabbccddee) { // do something } But somehow on 64-bit Windows, sizeof this struct always returns 8 bytes instead of 6 bytes. Any pointers are appreciated?

2021-10-03 06:58:28    分类:问答    c   struct   bit-fields   int64   structure-packing

##### 以符合标准的方式使用与数组相同类型的成员重新解释结构 [重复](Reinterpret struct with members of the same type as an array in a standard compliant way [duplicate])

2021-06-27 02:10:17    分类:技术分享    c++   language-lawyer   strict-aliasing   type-punning   structure-packing

##### 具有 char、double、int 和 at [重复] 的结构大小(Size of structure with a char, a double, an int and a t [duplicate])

2021-06-23 11:49:30    分类:技术分享    c++   structure-packing

##### 结构的大小如何随不同的数据类型而变化(how size of a structure varies with different data types)

2021-05-24 14:47:19    分类:技术分享    c++   c   structure   structure-packing

##### Extra bytes when declaring a member of a struct as uint32_t

I have a problem when using the uint32_t type from the stdint.h library. If I run the following code (on Ubuntu linux 11.10 x86_64, g++ version 4.6.1): #include "stdint.h" #include <iostream> using std::cout; typedef struct{ // api identifier uint8_t api_id; uint8_t frame_id; uint32_t dest_addr_64_h; uint32_t dest_addr_64_l; uint16_t dest_addr_16; uint8_t broadcast_radius; uint8_t options; // packet fragmentation uint16_t order_index; uint16_t total_packets; uint8_t rf_data[]; } xbee_tx_a; typedef struct{ // api identifier uint8_t api_id; uint8_t frame_id; uint16_t dest_addr_64_h; uint16_t

2021-05-10 21:53:37    分类:问答    c++   struct   sizeof   structure-packing

##### how size of a structure varies with different data types

I am using Linux 32 bit os, and GCC compiler. I tried with three different type of structure. in the first structure i have defined only one char variable. size of this structure is 1 that is correct. in the second structure i have defined only one int variable. here size of the structure is showing 4 that is also correct. but in the third structure when i defined one char and one int that means total size should be 5, but the output it is showing 8. Can anyone please explain how a structure is assigned? typedef struct struct_size_tag { char c; //int i; }struct_size; int main() { printf("Size

2021-05-08 20:07:20    分类:问答    c++   c   structure   structure-packing

##### C中struct的大小[重复](size of struct in C [duplicate])

2021-04-28 04:37:34    分类:技术分享    c   struct   structure-packing