Question

I have a large amount of constant data that I need to store in a header file. Due to the nature of the data (how its nested), I decided to use a structure that is initialized by the preprocessor.

I am trying to initialize these structs like so:

typedef struct s_PWM {
  uint8_t muxmode;
  char *name;
  char *path;
} PWM;

typedef struct s_PIN {
  char *name;
  uint8_t gpio;
  char *mux;
  uint8_t eeprom;
  PWM *pwm;
} PIN;

This would allow me to do something like

PIN p1 = P8_19;

to, in a sense, assemble a struct with the proper attributes.

Basically, you can send a pin into a function

pinMode(P8_19, OUTPUT)

This is the line in question

#define P8_19 ((PIN){"EHRPWM2A", 22, "gpmc_ad8", 14, (PWM*){4, "EHRPWM2A", "ehrpwm.2:0"}})

This is the warning

src/gpio.c:50:2: warning: excess elements in scalar initializer
src/gpio.c:50:2: warning: (near initialization for '(anonymous)')
src/gpio.c:50:2: warning: excess elements in scalar initializer
src/gpio.c:50:2: warning: (near initialization for '(anonymous)')

Does anyone have any ideas why this is happening? Am I incorrectly nesting the PWM* struct into the PIN struct?

Answer 1

Short answer: Yes.

Instead of having a pointer you should use the structure directly:

typedef struct s_PIN {
  char *name;
  uint8_t gpio;
  char *mux;
  uint8_t eeprom;
  PWM pwm;  /* Notice: not a pointer */
} PIN;

Also, you don’t need to do the casting:

#define P8_19 {"EHRPWM2A", 22, "gpmc_ad8", 14, {4, "EHRPWM2A", "ehrpwm.2:0"}}