Segmentation Fault while reading a file and trying to print the information-CodePudding

I writing a C code to read a .txt file, however I keep having this segmantation fault and I can't figure out what is going on, Could i please use some help?

Here's the code. More information below.

#include <stdlib.h>
#include <stdio.h>
#define MAX 256

int lerArq(int **I, char filename[MAX],int *h,int *w);

int main(){

    char option;
    char filename[MAX];
    int *h,*w;
    int **I;
    int i,j;

    printf("Q Quit (terminar o programa) \n L Ler um arquivo de imagens \n S Salvar a imagem em arquivo \n M Manter a imagem-entrada anterior \n B Binarizar a imagem-entrada \n C Calcular Contorno da imagem-entrada \n F Filtrar a imagem-entrada \n I Inverter a imagem-entrada \n R Rotular a imagem-entrada \n");
    printf("Digite a opção: \n");
    scanf("%c", &option);

    if(option=='l' || option=='L'){
        printf("Digite o nome do aquivo: \n");
        scanf("%s", filename);
        lerArq(I,filename,h,w);

    }


    return 0;
}

int lerArq(int **I, char filename[MAX],int *h,int *w){
    FILE *arq;
    arq=fopen(filename, "r");
    char line[5];
    int i,j;

    if(arq == NULL) {
        printf("ERRO: Não foi possível localizar o arquivo: %s! \n", filename);
        return 0;
    }

    fscanf(arq, "%s", line);
    fscanf(arq, "%d %d", w, h);
    fscanf(arq, "%s", line);


    printf("%d %d", *h, *w);

    fclose(arq);

    return 1;

}

The file that I am opening has the following aspect: The first and third line are irrelevant at this moment, they are only representing the format of the image(this file represents a black and white image). The second line, represents the number of rows and columns of the matrix.

Turns out that when I try to print the number of rows and columns, i get this error, segmentation fault.

P2
10 10
255
0 0 0 0 0 0 0 0 0 0
0 1 1 0 0 0 1 1 1 0
1 1 0 0 1 0 0 1 1 0
0 0 1 0 0 1 0 0 1 0
0 0 1 0 0 1 0 0 1 0
0 0 0 1 0 1 0 0 1 0
0 0 0 0 0 1 1 0 0 0
0 0 0 0 0 1 0 0 0 0
0 0 0 1 1 1 1 0 0 0
0 0 0 0 0 0 0 0 0 0

CodePudding user response：

int *h,*w;

h and w are indeterminate, they do not point to anything meaningful. Indeterminate pointers lead to undefined behaviour.

You could instead declare them as:

int h, w;

And then pass them to the letArq as:

lerArq(I, filename, &h, &w);

Or instead declare them where needed.

Side-notes: I is an unused parameter.

scanf and fscanf returns something, check for it.

return 0 and return 1 are equivalent to return EXIT_SUCCESS and return EXIT_FAILURE respectively.

The return value of letArq goes unused.