file reading line by line and printing not working on mac os but works fine in RHEL

Asked Apr 13 '20 at 18:14

Active Apr 13 '20 at 18:14

Viewed 19 times

The following code works in Linux but fails with a Segmentation Fault 11 on Mac OS (Catalina). What am I doing wrong?

Thanks.

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

int main (int argc, char *argv[]) {
        FILE *fp;
        char *line;
        int i;
        int max_line = 1000;
        if (--argc > 0) {
                if ( (fp = fopen(argv[1],"r")) != NULL) {
                        printf("File ptr:%p File Name:%s\n", fp, argv[1]);
                        while (fgets (line, sizeof(line), fp) != NULL) {
                                fputs(line, stdout);
                        }   
                        fclose(fp);
                } else {
                        printf("File cannot be opened:%s\n", argv[1]);
                }   
        }   
        return 0;
}

My input file:

asked Apr 13 '20 at 18:14

user3512999

3

You didn't allocate any memory for `line`. – Barmar Apr 13 '20 at 18:15
1

`if (--argc > 0)` in combination with `argv[1]` doesn't make sense. – Fiddling Bits Apr 13 '20 at 18:16
Use `char line[MAXLINELENGTH];` after defining a macro `MAXLINELENGTH` – Barmar Apr 13 '20 at 18:24
In your version, `sizeof(line)` is the size of a pointer, not the length of a string. – Barmar Apr 13 '20 at 18:24
Thank you. I wonder why it works fine in Linux though. – user3512999 Apr 13 '20 at 19:08

file reading line by line and printing not working on mac os but works fine in RHEL

0 Answers0