[src/trunk]: src/usr.bin/make make(1): clean up comments around JobPrintSpecials

[rillig <rillig%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/201ea5f06b26
branches:  trunk
changeset: 979055:201ea5f06b26
user:      rillig <rillig%NetBSD.org@localhost>
date:      Sat Dec 12 13:13:34 2020 +0000

description:
make(1): clean up comments around JobPrintSpecials

diffstat:

 usr.bin/make/job.c |  25 ++++++++++++++++---------
 1 files changed, 16 insertions(+), 9 deletions(-)

diffs (61 lines):

diff -r bf94b88a8c88 -r 201ea5f06b26 usr.bin/make/job.c
--- a/usr.bin/make/job.c        Sat Dec 12 12:56:56 2020 +0000
+++ b/usr.bin/make/job.c        Sat Dec 12 13:13:34 2020 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: job.c,v 1.383 2020/12/12 12:56:56 rillig Exp $ */
+/*     $NetBSD: job.c,v 1.384 2020/12/12 13:13:34 rillig Exp $ */
 
 /*
  * Copyright (c) 1988, 1989, 1990 The Regents of the University of California.
@@ -143,7 +143,7 @@
 #include "trace.h"
 
 /*     "@(#)job.c      8.2 (Berkeley) 3/19/94" */
-MAKE_RCSID("$NetBSD: job.c,v 1.383 2020/12/12 12:56:56 rillig Exp $");
+MAKE_RCSID("$NetBSD: job.c,v 1.384 2020/12/12 13:13:34 rillig Exp $");
 
 /*
  * A shell defines how the commands are run.  All commands for a target are
@@ -819,11 +819,9 @@
 }
 
 /*
- * The shell has no error control, so we need to be weird to get it to
- * ignore any errors from the command. If echoing is turned on, we turn it
- * off and use the echoTmpl template to echo the command. Leave echoing
- * off so the user doesn't see the weirdness we go through to ignore errors.
- * Set cmdTemplate to use the weirdness instead of the simple "%s\n" template.
+ * The shell has no built-in error control, so emulate error control by
+ * enclosing each shell command in a template like "{ %s \n } || exit $?"
+ * (configurable per shell).
  */
 static void
 JobPrintSpecialsEchoCtl(Job *job, ShellWriter *wr, CommandFlags *inout_cmdFlags,
@@ -835,6 +833,11 @@
        if (job->echo && inout_cmdFlags->echo) {
                ShellWriter_EchoOff(wr);
                ShellWriter_EchoCmd(wr, escCmd);
+
+               /*
+                * Leave echoing off so the user doesn't see the commands
+                * for toggling the error checking.
+                */
                inout_cmdFlags->echo = FALSE;
        } else {
                if (inout_cmdFlags->echo)
@@ -854,9 +857,13 @@
 JobPrintSpecials(Job *job, ShellWriter *wr, const char *escCmd, Boolean run,
                 CommandFlags *inout_cmdFlags, const char **inout_cmdTemplate)
 {
-       if (!run)
+       if (!run) {
+               /*
+                * If there is no command to run, there is no need to switch
+                * error checking off and on again for nothing.
+                */
                inout_cmdFlags->ignerr = FALSE;
-       else if (shell->hasErrCtl)
+       } else if (shell->hasErrCtl)
                ShellWriter_ErrOff(wr, job->echo && inout_cmdFlags->echo);
        else if (shell->runIgnTmpl != NULL && shell->runIgnTmpl[0] != '\0') {
                JobPrintSpecialsEchoCtl(job, wr, inout_cmdFlags, escCmd,