Hi guy I’m following a tutorial about sockets on Linux/ubuntu using C.
When I want to config the hints.ai_flags with AI_PASSIVE vs code response that is undefined. I searched in linux terminal with man getaddrinfo and it is in the manual. Anyone can help me with this?

I’ll shared part of my code:

#include <stdio.h>      
#include <string.h>     
#include <sys/types.h>  
#include <sys/socket.h> 
#include <netdb.h>      

struct addrinfo
{
    int ai_flags;             // AI_PASSIVE, AI_CANONNAME, etc.
    int ai_family;            // AF_INET, AF_INET6, AF_UNSPEC
    int ai_socktype;          // SOCK_STREAM, SOCK_DGRAM
    int ai_protocol;          // use 0 for "any"
    size_t ai_addrlen;        // size of ai_addr in bytes
    struct sockaddr *ai_addr; // struct sockaddr_in or _in6
    char *ai_canonname;       // full canonical hostname
    struct addrinfo *ai_next; // linked list, next node
};


int getaddrinfo(const char *node,    // e.g "www.example.com" or IP
                const char *service, // e.g "http" or port number
                const struct addrinfo *hints,
                struct addrinfo **res);

int main()
{

    int status;
    struct addrinfo hints;
    struct addrinfo *servinfo; // will point to the result

    memset(&hints, 0, sizeof hints); // make sure the struct is empty
    hints.ai_family = AF_UNSPEC;     // don't care IPv4 IPv6
    hints.ai_socktype = SOCK_STREAM; // TCP stream sockets
    hints.ai_flags = AI_PASSIVE;     // fill in my IP for me -> here appears undefined 
}

If I declare AI_PASSIVE like this, disappear the error:

#ifndef AI_PASSIVE
#define AI_PASSIVE 0x01
#endif