flexible-array-member

问题 From Use the correct syntax when declaring a flexible array member it says that when malloc is used for a header and flexible data when data[1] is hacked into the struct , This example has undefined behavior when accessing any element other than the first element of the data array. (See the C Standard, 6.5.6.) Consequently, the compiler can generate code that does not return the expected value when accessing the second element of data. I looked up the C Standard 6.5.6, and could not see how

来源： https://stackoverflow.com/questions/46233400/does-union-support-flexible-array-members

来源： https://stackoverflow.com/questions/46233400/does-union-support-flexible-array-members

来源： https://stackoverflow.com/questions/46233400/does-union-support-flexible-array-members

来源： https://stackoverflow.com/questions/46233400/does-union-support-flexible-array-members

问题 I have look on many places for this, and have tried using cast, but had no success. I have a struct in c like: struct t{ int x; struct y[0]; }; How would I resize the array of struct y? I tried the other types of this issue on SO (does python ctypes supports size-0 array?), but kept on getting this error. TypeError: incompatible types, y_Array_20 instance instead of y_Array_0 instance 回答1: My other answer you reference just has an example of returning a sized structure, and as the comments in

问题 I am getting this warning and weird bugs , when I try and run my program. rmi_pdu in the following structure contains a variable sized array..which I should use. Any info on this appreciated. struct rmi_message_s { /* Queue element containing Rmi message */ struct rmi_message_s *hnext; struct rmi_message_s *hprev; uint16_t gen_counter; /* Generation counter */ time_value send_time; uint8_t retry_count; TAILQ_ENTRY(rmi_message_s) rmi_message_next; rmi_message_pdu rmi_pdu; /* contains a

问题 By using flexible array members (FAMs) within structure types, are we exposing our programs to the possibility of undefined behavior? Is it possible for a program to use FAMs and still be a strictly conforming program? Is the offset of the flexible array member required to be at the end of the struct? The questions apply to both C99 (TC3) and C11 (TC1) . #include <stdio.h> #include <stdlib.h> #include <stddef.h> int main(void) { struct s { size_t len; char pad; int array[]; }; struct s *s =

问题 I understand more about pointers and stuff but I have no idea what I am doing wrong here. if i Have char *(*data)[] That would just be interpreted as "a pointer to an array of char pointers", right? Then I have a struct like this, typedef'd to be myStruct, redundant as it may be, but that's aside the point: typedef struct myStruct myStruct; struct myStruct{ int size; char *name; myStruct *(*array)[]; } Having looked around the site for similar posts, I got something like this: //let's say

问题 In C99, you commonly see the following pattern: struct Foo { int var1; int var2[]; }; Foo * f = malloc(sizeof(struct Foo) + sizeof(int)*n); for (int i=0; i<n; ++i) { f->var2[i] = p; } But not only is this bad C++, it's also illegal. You can achieve a similar effect in C++ like this: struct FooBase { void dostuff(); int var1; int var2[1]; }; template<size_t N> struct Foo : public FooBase { int var2[N-1]; }; Although this will work (in the methods of FooBase you can access var2[2] , var2[3] ,