Made a program to find either POSIX new lines or Windows newlines

[ImageJPEG]

I've been playing with Cygwin and C lately. I made this program to find new lines depending on what system they were created on.

Eventually, I'm wanting to create a converter to convert text files between POSIX and Windows.

Yes, I know one already exists but I want to try it myself.

Here's the code:

#include <stdio.h>
#include <stdint.h>
#include <string.h>


int main(int argc, char **argv) {
    int8_t FileData;
    uint8_t WinNewLine;
    FILE *fp = NULL;
    
    if(argc != 2) {
        fprintf(stderr, "Enter one file.\n");
        return 1;
    }
    
    fp = fopen(argv[1], "r");
    
    if(fp == NULL) {
        fprintf(stderr, "No file found.\n");
        return 1;
    }
    
    FileData = getc(fp);
    
    while(1) {
        WinNewLine = 0;
        
        if(FileData == '\r') {
            FileData = getc(fp);
            
            if(FileData == '\n') {
                printf("Found a new line!\n");
                WinNewLine = 1;
            }
        }
        
        if(FileData == '\n' && WinNewLine == 0)
            printf("Found POSIX new line!\n");
        
        FileData = getc(fp);
        
        if(feof (fp))
            break;
        }
    return 0;
    }

[rcgldr]

In the case of fread() used with fopen() with Windows, unless you open with "rb" (read binary mode), fread() will skip return "\r" characters, but I'm not sure about getc(). I'm not sure about all C libraries though. It won't hurt to have the check for "\r" either, other than the overhead.

[whiteflags]

getc() is a macro for a specific call to fread() probably. It would behoove the OP to check his implementation.

[ImageJPEG]

I'm a little lost.

Are you guys suggesting to implement fread() instead of getc()?

I'm a little lost with "...fread() will skip return "\r" characters...". I mean I think I understand what you're saying but not entirely.

So fread() will just skip over '\r' characters then? How can I determine if it's a new line under POSIX or Windows?

I'm assuming one of the main differences (and why Notepad doesn't work well with POSIX text files) with how text files are handled are how newlines are implemented in the either system?

[whiteflags]

To make it cross platform, you will have to open the file in "rb" mode and specifically check for "\r\n" (windows newline) or just '\n' (posix newline). You won't know the difference when the file is opened in "r" mode. I think windows just does the right thing for windows in that case.

[ImageJPEG]

If I open it in binary, I would need to search for 0x0D0A for Windows and just 0x0A for POSIX?

I'm thinking too much into it, aren't I?

https://www.cisco.com/c/en/us/td/doc...n_r/frf019.pdf

Use fread for binary mode though, right? getc won't get me anywhere since it wont be read as a text file.

[christop]

getc()/fgetc()/getchar() return an 'int', so you should save the return value in an 'int' variable. An added bonus (actually, a very common practice) is that you can check if you reached the end of the file (or encountered an I/O error) by comparing that value with 'EOF'. Then you don't have to call feof() to see if you reached the end of the file.