1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 | #include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include <assert.h>
#include "clog.h"
// ftell(…) returns the position in the file where we will read or write next.
// OK to copy/adapt this function if you understand it completely.
char const* write_file(char const* contents, char const* filename) {
FILE* fp = fopen(filename, "w");
fputs(contents, fp);
fclose(fp);
return filename;
}
int main(int argc, char* argv[]) {
char const* filename = "DOES_NOT_EXIST.txt";
logf_yellow("Open the file.\n");
FILE* fp = fopen(filename, "r");
// fopen(…) returns null if the file does not exist.
if(fp != NULL) {
// Jump to end of file.
fseek(fp, 0, SEEK_END); // 0 bytes from the end of the file
// Specifically: Set the file position indicator to the end of the file.
// Get current position (at end of file). That will be the length of the file
int position = ftell(fp);
printf("File \"%s\" contains %d characters.\n", filename, position);
fclose(fp);
}
return EXIT_SUCCESS;
}
/* vim: set tabstop=4 shiftwidth=4 fileencoding=utf-8 noexpandtab: */
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