C strings string comparisons always result in false - c

Question

I am trying to finding a string in a file. I wrote following by modifying code snippet present in man page of getline.
#define _GNU_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
int main(void)
{
FILE * fp;
char * line = NULL;
char *fixed_str = "testline4";
size_t len = 0;
ssize_t read;
fp = fopen("test.txt", "r");
if (fp == NULL)
exit(EXIT_FAILURE);
while ((read = getline(&line, &len, fp)) != -1) {
printf("Retrieved line of length %zu:\n", read);
printf("%s", line);
if (strcmp(fixed_str,line)==0)
printf("the match is found\n");
}
//printf("the len of string is %zu\n", strlen(fixed_str));
fclose(fp);
if (line)
free(line);
exit(EXIT_SUCCESS);
}
The problem is that result of strcmp is always false despite getline is successfully and correctly iterating over all lines in the file.
The length of fixed_str is 9 and that of equal string in file is 10 due to newline character (AM I RIGHT?). But comparing 9 chars with the help of strncmp still produces wrong result. I also ruled out the possibilities of caps and spaces so I think I am doing something very wrong
The test.txt is as below
test line1
test line2
test line3
testline4
string1
string2
string3
first name
I tried all entries but no success
NOTE: In my actual program I have to read fixed_str from another file

Answer 1

From the getline() man page (my emphasis):
getline() reads an entire line from stream, storing the address of
the buffer containing the text into *lineptr. The buffer is null-
terminated and includes the newline character, if one was found.
Your fixed_str has no newline.
Strip any newline character thus (for example):
char* nl = strrchr( line, '\n' ) ;
if(nl != NULL) *nl = `\0` ;
Or more efficiently since getline() returns the line length (in read in your case):
if(line[read - 1] == '\n' ) line[read - 1] = `\0` ;
Adding a '\n' to fixed_str may seem simpler, but is not a good idea because the last (or only) line in a file won't have one but may otherwise be a match.
Using strncmp() as described in your question should have worked, but without seeing the attempt it is hard to comment, but it is in any case a flawed solution since it would match all of the following for example:
testline4
testline4 and some more
testline4 12345.
Where fixed_str is taken from console or file input rather than a constant, the input method and data source may cause problems, as may the possibility of alternate line-end conventions. To make it more robust you might do:
// Strip any LF or CR+LF line end from fixed_str
char* line_end = strpbrk( fixed_str, "\r\n" ) ;
if( line_end != NULL ) *line_end = '\0' ;
// Strip any LF or CR+LF line end from line
line_end = strpbrk( line, "\r\n" ) ;
if( line_end != NULL ) *line_end = '\0' ;
Or the simpler (i.e. better) solution pointed out by #AndrewHenle:
// Strip any LF or CR+LF line end from fixed_str
fixed_str[strcspn(line, "\r\n")] = '\0';
// Strip any LF or CR+LF line end from line
line[strcspn(line, "\r\n")] = '\0';
That way either input can be compared regardless of lines ending in nothing, CR or CR+LF and the line end may even differ between the two inputs.