| 1 | // RUN: %clangxx -g %s -o %t && %run %t |
|---|---|
| 2 | |
| 3 | #include <assert.h> |
| 4 | #include <stdio.h> |
| 5 | |
| 6 | int main(int argc, char **argv) { |
| 7 | FILE *fp = fopen(filename: argv[0], modes: "r"); |
| 8 | assert(fp); |
| 9 | |
| 10 | // the file should be at least one character long, always |
| 11 | assert(fgetc(fp) != EOF); |
| 12 | // POSIX guarantees being able to ungetc() at least one character |
| 13 | assert(ungetc('X', fp) != EOF); |
| 14 | // check whether ungetc() worked |
| 15 | assert(getc(fp) == 'X'); |
| 16 | |
| 17 | assert(!fclose(fp)); |
| 18 | return 0; |
| 19 | } |
| 20 |