blob c7425802 (1057B) - Raw
1 #include "stdio_impl.h" 2 #include <errno.h> 3 4 int __fseeko_unlocked(FILE *f, off_t off, int whence) 5 { 6 /* Fail immediately for invalid whence argument. */ 7 if (whence != SEEK_CUR && whence != SEEK_SET && whence != SEEK_END) { 8 errno = EINVAL; 9 return -1; 10 } 11 12 /* Adjust relative offset for unread data in buffer, if any. */ 13 if (whence == SEEK_CUR && f->rend) off -= f->rend - f->rpos; 14 15 /* Flush write buffer, and report error on failure. */ 16 if (f->wpos != f->wbase) { 17 f->write(f, 0, 0); 18 if (!f->wpos) return -1; 19 } 20 21 /* Leave writing mode */ 22 f->wpos = f->wbase = f->wend = 0; 23 24 /* Perform the underlying seek. */ 25 if (f->seek(f, off, whence) < 0) return -1; 26 27 /* If seek succeeded, file is seekable and we discard read buffer. */ 28 f->rpos = f->rend = 0; 29 f->flags &= ~F_EOF; 30 31 return 0; 32 } 33 34 int __fseeko(FILE *f, off_t off, int whence) 35 { 36 int result; 37 FLOCK(f); 38 result = __fseeko_unlocked(f, off, whence); 39 FUNLOCK(f); 40 return result; 41 } 42 43 int fseek(FILE *f, long off, int whence) 44 { 45 return __fseeko(f, off, whence); 46 } 47 48 weak_alias(__fseeko, fseeko);