strchr function keep giving me core dumped error

Question

I am trying to write code that copy and print the word in text file on the screen with getline() and strchr() functions. so this is my code:

void read_teams(char* text)
{
    FILE *fp=fopen(text,"r");
    char* tname=NULL;
    size_t tname_size=0;
    while(getline(&tname,&tname_size,fp)!=EOF)
    {
        tname[strchr(tname,'\n')-tname]='\0';
        printf("%s\n",tname);
    }
    fclose(fp);
}

when it is read strchr function it's show:

Segmentation fault (core dumped)

so why? i have to use this function with getline ,so don't tell me to write my code in other way please.

you need to de allocate (free the buffer) that getline allocated for you! even if the program fails. adding to @user3121023, where is the free call in your code ? — Adam, May 14 '20 at 15:02
If the buffer does not contain a `\t` tab character, then `strchr()-tname` will be way before `tname`. That will cause a seg fault. — Paul Ogilvie, May 14 '20 at 15:03
Always check if `fopen` succeeds. There is absolutely no excuse for not doing it. And how do you know that `strchr` is the culprit? — Jabberwocky, May 14 '20 at 15:05
@RayanFarhat where is `'\t'` in the question? The question and answer do not make sense together. DV until fixed. — chux - Reinstate Monica, May 14 '20 at 15:37
@chux-ReinstateMonica my text file does not contain a '\t', and i am tried the code below and its works — RayanFarhat, May 14 '20 at 16:11
@chux-ReinstateMonica i am realy dont know but when i change it,its sloved,ask the other mate who called paul — RayanFarhat, May 14 '20 at 19:13

Paul Ogilvie · Accepted Answer · 2020-05-14T19:38:50.643

2

If the buffer does not contain a \n character, then strchr()-tname will be way before tname. That will cause a seg fault. So use:

while(getline(&tname,&tname_size,fp)!=EOF)
{
    char *p= strchr(tname,'\n');
    if (p)
        tname[p-tname]='\0';
    printf("%s\n",tname);
}

edited May 14 '20 at 19:38

answered May 14 '20 at 15:06

Paul Ogilvie

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Why does this answer talk about `'\t'` when it is not in the question? – chux - Reinstate Monica May 14 '20 at 19:18
@chux-ReinstateMonica, yep. Fixed it. – Paul Ogilvie May 14 '20 at 19:39

strchr function keep giving me core dumped error

1 Answers1