- stdout and make sure that the close succeeds. Otherwise, suppose that
- you go to the extreme of checking the return status of every function
- that does an explicit write to stdout. The last printf can succeed in
- writing to the internal stream buffer, and yet the fclose(stdout) could
- still fail (due e.g., to a disk full error) when it tries to write
- out that buffered data. Thus, you would be left with an incomplete
- output file and the offending program would exit successfully.
+ stdout and make sure that it succeeds before exiting. Otherwise,
+ suppose that you go to the extreme of checking the return status
+ of every function that does an explicit write to stdout. The last
+ printf can succeed in writing to the internal stream buffer, and yet
+ the fclose(stdout) could still fail (due e.g., to a disk full error)
+ when it tries to write out that buffered data. Thus, you would be
+ left with an incomplete output file and the offending program would
+ exit successfully. Even calling fflush is not always sufficient,
+ since some file systems (NFS and CODA) buffer written/flushed data
+ until an actual close call.