Passing pointer to array of struct
arrays, c, struct
Solution
`pass_func` expects an array of pointers to `client`
void pass_func(client* clients[]);
but you pass it
pass_func(&clients);
a pointer to an array of `client`s. So the `client` `clients[i]` is interpreted as a pointer to `client` in `pass_func`, but of course the bit-pattern is not a valid pointer to `client`, hence you're trying to access memory you shouldn't and get a segfault.
Either pass an array of pointers, or declare `pass_func`
void pass_func(client *clients);
(and then pass `pass_func(clients)` without the address-operator in main).
Your compiler warned you about passing an incompatible pointer type, though.
Problem
I'm trying to pass a pointer to an array of struct. This code should create an array of struct, writes to the vars in struct, and then prints them out (which works). Then I want to pass a pointer of that array of struct to another function and print out the array of struts. ``` #define PORT_NUMBER 5100 #define MAX_CLIENTS 5 #include <sys/types.h> #include <sys/socket.h> #include <netinet/in.h> #include <arpa/inet.h> #include <stdio.h> #include <stdlib.h> #include <unistd.h> #include <errno.h> #include <string.h> #include <pthread.h> typedef struct thread_args { int client_number; int connected; char client_name[1024]; } client; void pass_func(client* clients[]) int main() { struct thread_args clients[MAX_CLIENTS]; int i; for(i =0; i < MAX_CLIENTS; i++) { clients[i].client_number=i; strcpy(clients[i].client_name, "BOBBY"); } for(i =0; i < MAX_CLIENTS; i++) { printf("%d | %s\n", clients[i].client_number=i, clients[i].client_name); } printf("\n\n"); pass_func(&clients); } void pass_func(client* clients[]) { int i; for(i =0; i < MAX_CLIENTS; i++) { printf("%d | %s\n", clients[i]->client_number=i, clients[i]->client_name); } } ``` And this is the output: ``` $ gcc TEST.c -lpthread -o TEST.out TEST.c: In function ‘main’: TEST.c:41:3: warning: passing argument 1 of ‘pass_func’ from incompatible pointer type [enabled by default] TEST.c:22:6: note: expected ‘struct thread_args **’ but argument is of type ‘struct thread_args (*)[5]’ $ ./TEST.out 0 | BOBBY 1 | BOBBY 2 | BOBBY 3 | BOBBY 4 | BOBBY Segmentation fault ``` I've done about an hour of research and can't figure out why this is not working. Most of the examples I find are for C++, but not C. (And yes I know many of the header files I've included are not necessary for this code; this is just a segment of my original code.)