What does this mean? #define MQTTString_initializer {NULL, {0, NULL}}

shijizai

What does this mean? #define MQTTString_initializer {NULL, {0, NULL}} [Copy link]

#define MQTTString_initializer {NULL, {0, NULL}}

What does this mean? I know that MQTTString_initializer is equivalent to {NULL, {0, NULL}}, but what does {NULL, {0, NULL}} mean?

Jacktang

I don't quite understand

Waiting for other netizens to answer

lcofjp

This is to be assigned to the structure for initialization.

zhangdaoyu

You need to look at the occasion of the call! You can judge according to the occasion, maybe you will understand everything when you see the application occasion

freebsder

struct MQTTString s = MQTTString_initializer;

This is used for initialization

gzwangyu

You can understand it by replacing {NULL, {0, NULL}} with MQTTString_initializer.