检测系统换行符

test_lf_cr.c

/*
 ============================================================================
 Name        : test_lf_cr.c
 Author      : shaobin0604
 Version     :
 Copyright   : Your copyright notice
 Description : This small piece of code is used to detect the new line character
               on different platforms.
               
               eg.
               * Unix-like  LF    (0x0a)
               * Mac        CR    (0x0d)
               * Windows    CR+LF (0x0d 0x0a)
 ============================================================================
 */
#include <stdio.h>
#include <stdlib.h>

int main(int argc, char **argv) {
	int i;
	int read;
	FILE* fp;
	if ((fp = fopen("file1", "w")) == NULL) {
		printf("error open file file1!\n");
		exit(1);
	}
	printf("1. write '\\n' to file\n");
	fputc('\n', fp);
	fclose(fp);

	if ((fp = fopen("file1", "r")) == NULL) {
		printf("error open file file1!\n");
		exit(1);
	}

	printf("2. read file in text mode\n");
	int c;
	while (EOF != (c = fgetc(fp)))
		printf("0x%02x ", c);
	fclose(fp);

	if ((fp = fopen("file1", "rb")) == NULL) {
		printf("error open file file1!\n");
		exit(1);
	}

	char data[2];
	if (2 != (read = fread(data, sizeof(char), 2, fp))) {
		if (ferror(fp)) {
			printf("error read file file1!\n");
			exit(1);
		}
		if (feof(fp)) {
			/*
			 * do nothing, just swallow it
			 */
		}
	}
	printf("\n3. read file in binary mode\n");
	for (i = 0; i < read; i++) {
		printf("0x%02x ", data[i]);
	}
	fclose(fp);

	printf("\n4. conclusion\n");
	if (read == 2 && data[0] == (char) 0x0d && data[1] == (char) 0x0a) {
		printf("the new line character on this platform is CR+LF\n");
	} else if (read == 1) {
		if (data[0] == (char) 0x0a)
			printf("the new line character on this platform is LF\n");
		else if (data[0] == (char) 0x0d)
			printf("the new line character on this platform is CR\n");
	}
	return 0;
}