Question

When I tried to initialize a global array that contains structure elements, I got the ” error: initializer element is not constant”

a.h

---

#define MAX_MSG_NUM 20
#define NAME_SIZE   15
#define MAX_QUE_NUM  10

typedef struct {
   int         index;
   int         tid;
   int         front;
   int         rear;
   char        name[NAME_SIZE];
   char        msgbuf[MAX_MSG_NUM];
} THREAD;

typedef enum {
   I1        = 0,
   I2        = 1,
   I3        = 2,
   I4        = 3
} DMTHREAD;

a.c

---

THREAD   a[MAX_MSG_NUM];
THREAD   b[MAX_MSG_NUM];
THREAD   c[MAX_MSG_NUM];

THREAD   T[MAX_QUE_NUM] = {
   {I1,   0, 0, 0, "CONFIG1",      a[MAX_MSG_NUM]},
   {I2,   0, 0, 0, "CONFIG2",      b[MAX_MSG_NUM]},
   {I3,   0, 0, 0, "CONFIG3",       c[MAX_MSG_NUM]},
   0
};

---

GCC compiler.

bash-3.2$ gcc -g a.h a.c
a.c:8: error: initializer element is not constant
a.c:8: error: (near initialization for 'T[0].msgbuf[0]')
a.c:9: error: initializer element is not constant
a.c:9: error: (near initialization for 'T[1].msgbuf[0]')
a.c:10: error: initializer element is not constant
a.c:10: error: (near initialization for 'T[2].msgbuf[0]')

Thanks for help.

Enlightened by your answers, I changed the code and it works fine now.

MSG   T[MAX_QUE_NUM] = {
           {I1,   0, 0, 0, "CONFIG1",      {0}},
           {I2,   0, 0, 0, "CONFIG2",      {0}},
           {I3,   0, 0, 0, "CONFIG3",      {0}}, 
           0,
    }

Thank you for your answers.

Answer 1

a[MAX_MSG_NUM] is indeed non-constant. It also denotes a Thread instance, which happens to be outside the array you defined earlier, and does not match the type you should pass there (char[]).

So it is wrong on so many levels.