I need to write a program in C reading in a big XML file with getline, the problem is only 2085 of the approxemately 3 billion lines are read. In the following code the problem occurs.

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

int main()                                          
{
    size_t l = 0;
    char *line;

    line = NULL;
    while (getline(&line,&l,stdin)>0) {

        getline(&line,&l,stdin);
        printf("%s\n", line);
        printf("%i\n", i);

        free(line);
        line = NULL;
    }
    return 0;
}

My first goal would be to display the lines, with printf so I can work with that. Neither line from 2080 til 2090 is empty. If I change the loop-condition to >=0 about 80.000 are read in and if I comment the printf out, about 130.00 lines. But instead I get an segmentation error. Which I really don't know how to solve in this case. I am using Visual Studio Code to edit and MYSYS2 MinGW to run the Code, on Windows 11. First the getline Function couldn't be found, I resolved it by Copy-Pasting the getline Code of this page, because the #include header's seemed not to work.

CodePudding user response：

1. You skip every second line as you read the line in the while then you read it again in the while body
2. You have a memory leak (same reason as point 1)

int main(void)                                          
{
    size_t l = 0;
    ssize_t retVal;
    char *line;

    line = NULL;
    do 
    {
        if((retVal = getline(&line,&l,stdin)) != -1)
        {
            printf("Buff_size:%zu Line_length: %zd Line:\"%s\"\n", l, retVal, line);

        }
    }while(retVal != -1);
    free(line);
    return 0;
}