diff options
Diffstat (limited to 'output.c')
| -rw-r--r-- | output.c | 56 |
1 files changed, 54 insertions, 2 deletions
@@ -178,9 +178,9 @@ set_append_mode (int fd) /* Semaphore for use in -j mode with output_sync. */ static sync_handle_t sync_handle = -1; -#define STREAM_OK(_s) ((fcntl (fileno (_s), F_GETFD) != -1) || (errno != EBADF)) +#define STREAM_OK(_s) ((fcntl (fileno (_s), F_GETFD) != -1) || (errno != EBADF)) -#define FD_NOT_EMPTY(_f) ((_f) != OUTPUT_NONE && lseek ((_f), 0, SEEK_END) > 0) +#define FD_NOT_EMPTY(_f) ((_f) != OUTPUT_NONE && lseek ((_f), 0, SEEK_END) > 0) /* Set up the sync handle. Disables output_sync on error. */ static int @@ -460,6 +460,53 @@ output_tmpfile (char **name, const char *template) } +/* This code is stolen from gnulib. + If/when we abandon the requirement to work with K&R compilers, we can + remove this (and perhaps other parts of GNU make!) and migrate to using + gnulib directly. + + This is called only through atexit(), which means die() has already been + invoked. So, call exit() here directly. Apparently that works...? +*/ + +/* Close standard output, exiting with status 'exit_failure' on failure. + If a program writes *anything* to stdout, that program should close + 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. + + Besides, it's wasteful to check the return value from every call + that writes to stdout -- just let the internal stream state record + the failure. That's what the ferror test is checking below. + + It's important to detect such failures and exit nonzero because many + tools (most notably 'make' and other build-management systems) depend + on being able to detect failure in other tools via their exit status. */ + +static void +close_stdout (void) +{ + int prev_fail = ferror (stdout); + int fclose_fail = fclose (stdout); + + if (prev_fail || fclose_fail) + { + if (fclose_fail) + error (NILF, _("write error: %s"), strerror (errno)); + else + error (NILF, _("write error")); + exit (EXIT_FAILURE); + } +} + + void output_init (struct output *out) { @@ -487,6 +534,11 @@ output_init (struct output *out) lose output due to overlapping writes. */ set_append_mode (fileno (stdout)); set_append_mode (fileno (stderr)); + +#ifdef HAVE_ATEXIT + if (STREAM_OK (stdout)) + atexit (close_stdout); +#endif } void |