"paste" patch to report errno values better

[Paul Eggert]

I installed this, to fix some errno glitches that I noticed when
writing the other "paste" patches.

2004-09-02  Paul Eggert  <address@hidden>

        Output correct errno-related diagnostic on "paste" I/O errors.
        * src/paste.c (write_error, xputchar): New functions.
        (paste_parallel): Use correct errno value after input error.
        (paste_parallel, paste_serial): Report errno value after output error.

Index: paste.c
===================================================================
RCS file: /home/eggert/coreutils/cu/src/paste.c,v
retrieving revision 1.75
retrieving revision 1.76
diff -p -u -r1.75 -r1.76
--- paste.c     3 Sep 2004 01:23:15 -0000       1.75
+++ paste.c     3 Sep 2004 01:35:33 -0000       1.76
@@ -134,6 +134,25 @@ collapse_escapes (char const *strptr)
   delim_end = strout;
 }
 
+/* Report a write error and exit.  */
+
+static void write_error (void) ATTRIBUTE_NORETURN;
+static void
+write_error (void)
+{
+  error (EXIT_FAILURE, errno, _("write error"));
+  abort ();
+}
+
+/* Output a single byte, reporting any write errors.  */
+
+static inline void
+xputchar (char c)
+{
+  if (putchar (c) < 0)
+    write_error ();
+}
+
 /* Perform column paste on the NFILES files named in FNAMPTR.
    Return true if successful, false if one or more files could not be
    opened or read. */
@@ -197,14 +216,17 @@ paste_parallel (size_t nfiles, char **fn
       for (i = 0; i < nfiles && files_open; i++)
        {
          int chr IF_LINT (= 0);        /* Input character. */
+         int err IF_LINT (= 0);        /* Input errno value.  */
          size_t line_length = 0;       /* Number of chars in line. */
 
          if (fileptr[i])
            {
              chr = getc (fileptr[i]);
+             err = errno;
              if (chr != EOF && delims_saved)
                {
-                 fwrite (delbuf, sizeof (char), delims_saved, stdout);
+                 if (fwrite (delbuf, 1, delims_saved, stdout) != delims_saved)
+                   write_error ();
                  delims_saved = 0;
                }
 
@@ -213,8 +235,9 @@ paste_parallel (size_t nfiles, char **fn
                  line_length++;
                  if (chr == '\n')
                    break;
-                 putc (chr, stdout);
+                 xputchar (chr);
                  chr = getc (fileptr[i]);
+                 err = errno;
                }
            }
 
@@ -226,7 +249,7 @@ paste_parallel (size_t nfiles, char **fn
                {
                  if (ferror (fileptr[i]))
                    {
-                     error (0, errno, "%s", fnamptr[i]);
+                     error (0, err, "%s", fnamptr[i]);
                      ok = false;
                    }
                  if (fileptr[i] == stdin)
@@ -250,10 +273,12 @@ paste_parallel (size_t nfiles, char **fn
                      /* No.  Some files were not closed for this line. */
                      if (delims_saved)
                        {
-                         fwrite (delbuf, sizeof (char), delims_saved, stdout);
+                         if (fwrite (delbuf, 1, delims_saved, stdout)
+                             != delims_saved)
+                           write_error ();
                          delims_saved = 0;
                        }
-                     putc ('\n', stdout);
+                     xputchar ('\n');
                    }
                  continue;     /* Next read of files, or exit. */
                }
@@ -275,9 +300,9 @@ paste_parallel (size_t nfiles, char **fn
              if (i + 1 != nfiles)
                {
                  if (chr != '\n' && chr != EOF)
-                   putc (chr, stdout);
+                   xputchar (chr);
                  if (*delimptr != EMPTY_DELIM)
-                   putc (*delimptr, stdout);
+                   xputchar (*delimptr);
                  if (++delimptr == delim_end)
                    delimptr = delims;
                }
@@ -286,7 +311,7 @@ paste_parallel (size_t nfiles, char **fn
                  /* If the last line of the last file lacks a newline,
                     print one anyhow.  POSIX requires this.  */
                  char c = (chr == EOF ? '\n' : chr);
-                 putc (c, stdout);
+                 xputchar (c);
                }
            }
        }
@@ -345,24 +370,24 @@ paste_serial (size_t nfiles, char **fnam
              if (charold == '\n')
                {
                  if (*delimptr != EMPTY_DELIM)
-                   putc (*delimptr, stdout);
+                   xputchar (*delimptr);
 
                  if (++delimptr == delim_end)
                    delimptr = delims;
                }
              else
-               putc (charold, stdout);
+               xputchar (charold);
 
              charold = charnew;
            }
          saved_errno = errno;
 
          /* Hit EOF.  Process that last character. */
-         putc (charold, stdout);
+         xputchar (charold);
        }
 
       if (charold != '\n')
-       putc ('\n', stdout);
+       xputchar ('\n');
 
       if (ferror (fileptr))
        {