Thread: Exc_bad_access

Hi, I am writing a tool in C, but can't get rid of this error. I get a "EXC_BAD_ACCESS" on line afile = fopen(argv[3], "r");, which is right after where I try to init a few matrices.

Code:

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <math.h>

int main (int argc, const char * argv[])
{  
    int w, h;
    char line[64];
    char * pch;
    int frame, idx_x, idx_y, depth;
    int mvx, mvy;
    FILE *afile;
    FILE *bfile;
    
    if (argc != 5) {
        printf("Usage: [...]");
        exit(1);
    }
    
    w = atoi(argv[1]);
    h = atoi(argv[2]);

    int mtrx_depth[w][h];
    int mtrx_mvx[w][h];
    int mtrx_mvy[w][h];
    
    afile = fopen(argv[3], "r");
    bfile = fopen(argv[4], "r");
        
    if (afile == NULL || bfile == NULL) {
        printf("ERROR: Could not read file");
        fclose(afile==NULL ? bfile : afile);
        exit(1);
    }
    
// Main loop 1: iterate over depth values in bfile, fill table
    while (fgets(line, sizeof line, bfile) != NULL) {
            pch = strtok(line, ",");
        frame = atoi(pch);
            pch = strtok(NULL, ",");
        idx_x = atoi(pch);
            pch = strtok(NULL, ",");
        idx_y = atoi(pch);
            pch = strtok(NULL, ",");
        depth = atoi(pch);
        mtrx_depth[idx_x][idx_y] = depth;
    }
    
// Main loop 2: iterate over lines in afile, fill table
    while (fgets(line, sizeof line, afile) != NULL) {
        // Read line vars
        {
        pch = strtok(line, "\t");
        frame = atoi(pch);
        pch = strtok(NULL, "\t");
        mvx = atoi(pch);
        pch = strtok(NULL, "\t");
        mvy = atoi(pch);
        }
        mtrx_mvx = mvx;
        mtrx_mvy = mvy;
    }
    fclose(afile);
    fclose(bfile);
    return 0;
}

The error:

Running…
Program received signal: “EXC_BAD_ACCESS”.
sharedlibrary apply-load-rules all
warning: Unable to restore previously selected frame.
No memory available to program now: unsafe to call malloc
Data Formatters temporarily unavailable, will re-try after a 'continue'. (Unknown error loading shared library "/Developer/Applications/Xcode.app/Contents/PlugIns/GDBMIDebugging.xcplugin/Contents/Resources/PBGDBIntrospectionSupport.A.dylib")

My guess is it's something to do with a (lack of) malloc for the three matrices, but I thought it worked earlier and don't really see how I should malloc them then...

Any help/suggestions would be welcome.

Thanks in advance!

Xavier

I suppose that depends on how big w and h are. Variable-length arrays may still end up on the stack, I think, and you've only got 1MB on the stack (usually) to play with.

That seemed to do it, thanks! Will test more extensively tomorrow, but it's looking good