I'm losing binary data when using fseek in c - c

Question

I wrote a function that is responsible for moving to a binary file and editing its bytes
int replace(FILE *binaryFile, long offset, unsigned char *replaced, int length) {
if (binaryFile != NULL) {
for (int i = 0; i < length; i++) {
fseek(binaryFile, offset + i, SEEK_SET);
fwrite(&replaced[i], sizeof(*replaced), 1, binaryFile);
}
fclose(binaryFile);
return 0;
}
else return -1;
}
When I use this function, I encounter a strange problem
All data in the file is filled with NULL bytes
And only one of the addresses in the file changes
Example:
FILE* fp = fopen("target.bin", "wb");
replace(fp, 0x57d8b0, "\x1E\xFF\x2F\xE1", 4);
replace(fp, 0x57c770, "\x01\x00\xA0\xE3\x1E\xFF\x2F\xE1", 8);
Result:
0x57c770: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
...
0x57d8a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x57d8b0: 1e ff 2f e1
Correct result:
0x57c770: 01 00 A0 E3 1E FF 2F E1 ...
...
0x57d8a0: 9c c4 0a ea 70 d2 68 00 44 d4 68 00 10 d1 68 00
0x57d8b0: 1e ff 2f e1 18 b0 8d e2 02 8b 2d ed 18 d0 4d e2
Please help me to solve the function problem or other problems.

Answer 1

wb is not correct. It clobbers the file.
From here,
Mode
Meaning
Explanation
If already exists
If does not exist
"r"
read
Open a file for reading
read from start
failure to open
"w"
write
Create a file for writing
destroy contents
create new
"a"
append
Append to a file
write to end
create new
"r+"
read extended
Open a file for read/write
read from start
error
"w+"
write extended
Create a file for read/write
destroy contents
create new
"a+"
append extended
Open a file for read/write
write to end
create new
You want r+b.
Also, you close the file handle in replace, which is premature. This should be done outside of replace, after you're done with the handle.
As an aside, you shouldn't be doing a number of seeks and writes of length one equal to length; you should be doing one seek and one write of length length.