Struct defined in the .c auxiliary file (with definition of functions and structs) is not recognized in main

Question

Struct defined in the .c auxiliary file (with definition of functions and structs) is not recognized in main

Navigation

#1 by (0 votes)

1

I'm doing a project in C, and I have 3 files:

1 .c containing the definitions of functions and structs.

1 .h containing the prototypes of these functions and structs

ae1 .c that contains main.

In the .c with the definitions, I defined the struct:

typedef struct vector {

    int numDePosicoes;
    double vetor[5000];

}ESTRUCT;

And in the main method, I try to create an instance of this struct as follows:

int main(int argc,char* argv[]) {

    ESTRUCT vetor;

    //criando separadamente um ponteiro para a struct
    ESTRUCT *ponteiroPraVetor = &vetor;

But gcc accuses the error: "error: unknown type name 'ESTRUCT'"

In both the creation of the struct, and in the creation of the pointer for it.

Note: I am using a Makefile to mount the program, follow it below:

CFLAGS=-Wall

Roteiro5exe:    mainr5.o    Roteiro5.o

mainr5.o:   mainr5.c    Roteiro5.h

Roteiro5.o: Roteiro5.c  Roteiro5.h

clean:
    rm *.o

NOTE: When I put all the code in the same file, and simply compile it, it works. Maybe the problem is in the makefile. Can anyone see it?

c struct gcc makefile

asked by anonymous 15.07.2016 / 17:05

1 answer

Error filtering form values by comparing two arrays How to create an Advertising Banner for my App? Ionic and Angular Js [closed]

score 0 · Answer 1

It seems to me that you are confusing statement with definition. Whenever you want to use something, you have to declare it. Declaring means introducing something to the system. For example:

extern int a;
typedef struct { int a;} X;
void print();

Defining means giving a body for statements. You can imagine how to create a space in memory, where the statements will live. For example:

int a = 1;
X k;
void print() {}

Definitions are usually placed in a .c file, whereas declarations are usually placed in an .h file. This is necessary because whenever you use a setting, you have to see the statement.

That's why, in your case, the ESTRUCT statement is in the wrong place. This is not a definition, it is a statement and it should be seen in all files where you want to use it. So you should declare it in a .h file and include this file where the main function is, which by the way, is where you make a definition when writing:

ESTRUCT vetor;