summaryrefslogtreecommitdiff
path: root/output.c
diff options
context:
space:
mode:
Diffstat (limited to 'output.c')
-rw-r--r--output.c56
1 files changed, 54 insertions, 2 deletions
diff --git a/output.c b/output.c
index 2e69c6d..6463432 100644
--- a/output.c
+++ b/output.c
@@ -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