From 2a1f89e5d941a77e8c93ad0a5fe78229a4207d61 Mon Sep 17 00:00:00 2001
From: Rob Landley <rob@landley.net>
Date: Tue, 16 Apr 2019 16:53:27 -0500
Subject: Add argument to xflush() so it can test for stdout err without
 flushing.

---
 lib/lib.h             |  2 +-
 lib/xwrap.c           | 16 +++++++++-------
 toys/other/hexedit.c  |  2 +-
 toys/pending/arping.c |  1 -
 toys/pending/vi.c     |  4 ++--
 toys/posix/echo.c     |  4 +---
 toys/posix/head.c     |  1 -
 7 files changed, 14 insertions(+), 16 deletions(-)

diff --git a/lib/lib.h b/lib/lib.h
index 0f15484e..6ec2c696 100644
--- a/lib/lib.h
+++ b/lib/lib.h
@@ -129,7 +129,7 @@ void xputsl(char *s, int len);
 void xputsn(char *s);
 void xputs(char *s);
 void xputc(char c);
-void xflush(void);
+void xflush(int flush);
 void xexec(char **argv);
 pid_t xpopen_both(char **argv, int *pipes);
 int xwaitpid(pid_t pid);
diff --git a/lib/xwrap.c b/lib/xwrap.c
index 12170ada..a242cd53 100644
--- a/lib/xwrap.c
+++ b/lib/xwrap.c
@@ -54,7 +54,7 @@ void xexit(void)
 
     free(al);
   }
-  if (fflush(0) || ferror(stdout)) if (!toys.exitval) perror_msg("write");
+  xflush(1);
   _xexit();
 }
 
@@ -139,9 +139,11 @@ char *xmprintf(char *format, ...)
   return ret;
 }
 
-void xflush(void)
+// if !flush just check for error on stdout without flushing 
+void xflush(int flush)
 {
-  if (fflush(stdout) || ferror(stdout)) perror_exit("write");
+  if ((flush && fflush(0)) || ferror(stdout))
+    if (!toys.exitval) perror_msg("write");
 }
 
 void xprintf(char *format, ...)
@@ -151,7 +153,7 @@ void xprintf(char *format, ...)
 
   vprintf(format, va);
   va_end(va);
-  xflush();
+  xflush(0);
 }
 
 // Put string with length (does not append newline)
@@ -164,7 +166,7 @@ void xputsl(char *s, int len)
     len -= out;
     s += out;
   }
-  xflush();
+  xflush(0);
 }
 
 // xputs with no newline
@@ -177,13 +179,13 @@ void xputsn(char *s)
 void xputs(char *s)
 {
   puts(s);
-  xflush();
+  xflush(0);
 }
 
 void xputc(char c)
 {
   if (EOF == fputc(c, stdout)) perror_exit("write");
-  xflush();
+  xflush(0);
 }
 
 // This is called through the XVFORK macro because parent/child of vfork
diff --git a/toys/other/hexedit.c b/toys/other/hexedit.c
index 06a96a22..809340a1 100644
--- a/toys/other/hexedit.c
+++ b/toys/other/hexedit.c
@@ -180,7 +180,7 @@ void hexedit_main(void)
 
     // Display cursor and flush output
     highlight(x, y, ro ? 3 : side);
-    xflush();
+    xflush(1);
 
     // Wait for next key
     key = scan_key(keybuf, -1);
diff --git a/toys/pending/arping.c b/toys/pending/arping.c
index be43cab1..6007845b 100644
--- a/toys/pending/arping.c
+++ b/toys/pending/arping.c
@@ -166,7 +166,6 @@ static void recv_from(struct sockaddr_ll *from, int *recv_len)
       gettimeofday(&tval, NULL);
       delta = (tval.tv_sec * 1000000ULL + (tval.tv_usec)) - TT.sent_at;
       xprintf(" %u.%03ums\n", delta / 1000, delta % 1000);
-      xflush();
     }
   }
   TT.rcvd_nr++;
diff --git a/toys/pending/vi.c b/toys/pending/vi.c
index 31516b55..2beedf49 100644
--- a/toys/pending/vi.c
+++ b/toys/pending/vi.c
@@ -543,7 +543,7 @@ void vi_main(void)
   //we dont get scroll log full of junk
   tty_esc("?1049h");
   tty_esc("H");
-  xflush();
+  xflush(1);
   draw_page();
   while(1) {
     key = scan_key(keybuf, -1);
@@ -821,7 +821,7 @@ static void draw_page()
     tty_esc("0m");
   } else tty_jump(cx_scr, cy_scr);
 
-  xflush();
+  xflush(1);
 
 }
 
diff --git a/toys/posix/echo.c b/toys/posix/echo.c
index 639f87ab..63eb1981 100644
--- a/toys/posix/echo.c
+++ b/toys/posix/echo.c
@@ -65,7 +65,7 @@ void echo_main(void)
         int slash = *(c++), n = unescape(slash);
 
         if (n) out = n;
-        else if (slash=='c') goto done;
+        else if (slash=='c') return;
         else if (slash=='0') {
           out = 0;
           while (*c>='0' && *c<='7' && n++<3) out = (out*8)+*(c++)-'0';
@@ -90,6 +90,4 @@ void echo_main(void)
 
   // Output "\n" if no -n
   if (!(toys.optflags&FLAG_n)) putchar('\n');
-done:
-  xflush();
 }
diff --git a/toys/posix/head.c b/toys/posix/head.c
index 7e34a714..38ab919e 100644
--- a/toys/posix/head.c
+++ b/toys/posix/head.c
@@ -40,7 +40,6 @@ static void do_head(int fd, char *name)
     // Print an extra newline for all but the first file
     if (TT.file_no) xprintf("\n");
     xprintf("==> %s <==\n", name);
-    xflush();
   }
 
   while ((toys.optflags&FLAG_c) ? bytes : lines) {
-- 
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