Unusual struct in c

user_10498285 0
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how should I understand the array of two strings?

static struct S1 {
    char c[3], *s;
} s1 = {"abc", "def" };

Probably the question is not correct but I have difficulties to understand how it works

struct c
4 Answers

S1.c has space for 3 bytes and S1.s is a pointer to a string.

the first part defines the structure:

struct S1 {
    char c[3], *s;
};

The next part creates an instance of this type and initializes it with a few values: 

static struct S1 s1 = {"abc", "def" };

static is not part of the struct definition. It refers to the visibility of the instance variable.

user_3131450

The first initialiser "abc" copies those 3 characters into the member char c[3]. There is no room for a string terminator so it is a simple array and cannot be treated as a string.

The second initialiser "def" copies a pointer into the member char *s. It points to the string literal "def" which is placed in read-only memory. It can be treated as a string but cannot be modified.

user_41429240

The initializer {"abc", "def" } is not an array. In this context, it is used to initialize an instance of the struct.

user_14405650

This is not the same code, but might help to understand what is going on, 1st of all it not array. The structure have 2 elements.

#include <stdio.h>

struct S1 {
    char c[3];
    char* s;   
};

int main(void) {
    struct S1 s1 = { .c = "abc", .s = "def" };
    printf("s1.c: %.*s\n", 3, (char*) s1.c);
    printf("s1.s: %s\n", s1.s);
}
user_67290610
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