CODEWITHSUNDEEP
c++c
user3239138
user3239138

Reputation: 143

use of undeclared identifier

static void cmd_help(char *dummy)    
{

    struct command *c;
    puts("commands are:");
    c = mscp_commands;
    do {
          printf("%-8s - %s\n", c->name ? c->name : "", c->help);
    } while (c++->name != NULL);

}

struct command mscp_commands[] = {
    ....
};

I am trying to convert a program from C into C++. The qualification is that it compiles through g++;

I am getting this error:

error: use of undeclared identifier 'mscp_commands' c = mscp_commands;

I'm thinking that it has to do something with the function not being able to "see" the struct command. Can someone help please?

Upvotes: 0

Views: 4343

Answers (2)

Kirill Kobelev
Kirill Kobelev

Reputation: 10557

In C and C++ everything should be declared or defined before use. When compiler finds an identifier that it has not ever seen before, like your mscp_commands in c = mscp_commands; it issues an error. You need to move definition of mscp_commands up or at least declare it like

extern struct command mscp_commands[];

before using this identifier.

These languages have concept of "forward declaration". Such declarations say that name Blah is structure or enum without giving any further details. But at least this should be present. Otherwise it is a syntax error. In your example there is nothing about command.

Upvotes: 1

Barış Uşaklı
Barış Uşaklı

Reputation: 13532

Move 

struct command mscp_commands[] = {

};

before the cmd_help function.

Upvotes: 0

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