Valgrind-Uninitialised value error with getline() function

Question

I want to read multiple lines from a text file by a loop, but I always get Conditional jump or move depends on uninitialised value(s) error in my getline() line.

My code:

char *string;
size_t len = 0;   

while (getline(&string, &len, fileStream) != -1) { // error happens this line   
    // do something  
}

free(string);   
fclose(fileSream);   

I tried but failed to fix it. Any solutions will be appreciated.

Answer 1

You need to do either of below.

1. set char *string = NULL; and len to 0. ^{[[ Preferred Method ]]}

2. allocate memory to char *string and send the size of allocated memory using len.

Related quotes from man page for referrence

   If *lineptr is set to NULL and *n is set 0 before the call, then
   getline() will allocate a buffer for storing the line.  This buffer
   should be freed by the user program even if getline() failed.

   Alternatively, before calling getline(), *lineptr can contain a
   pointer to a malloc(3)-allocated buffer *n bytes in size.  If the
   buffer is not large enough to hold the line, getline() resizes it
   with realloc(3), updating *lineptr and *n as necessary.