Re: use execute module in m4

[Bruno Haible]

Hi Eric,

> the execute module outputs an unwanted warning message when a signal
> is encountered in the child; m4 would rather handle the warning itself to
> give it consistent formatting.  OK to apply the gnulib patch?

Makes sense indeed to leave to the caller error messages which the caller
can do. Applied as below.


2009-03-01  Eric Blake  <address@hidden>
            Bruno Haible  <address@hidden>

        * lib/wait-process.h (wait_subprocess): Describe effect of termsigp on
        error messages.
        * lib/wait-process.c (wait_subprocess): Omit error message about
        deadly signal sent to the child of termsigp != NULL.

--- lib/wait-process.h.orig     2009-03-01 18:11:48.000000000 +0100
+++ lib/wait-process.h  2009-03-01 18:08:55.000000000 +0100
@@ -48,9 +48,10 @@
      slave process.
    - If exit_on_error is true, any error will cause the main process to exit
      with an error status.
-   - If termsigp is not NULL, *termsig will be set to the signal that
+   - If termsigp is not NULL: *termsig will be set to the signal that
      terminated the subprocess (if supported by the platform: not on native
-     Windows platforms), otherwise 0.
+     Windows platforms), otherwise 0, and the error message about the signal
+     that terminated the subprocess will be omitted.
    Prerequisites: The signal handler for SIGCHLD should not be set to SIG_IGN,
    otherwise this function will not work.  */
 extern int wait_subprocess (pid_t child, const char *progname,
--- lib/wait-process.c.orig     2009-03-01 18:11:48.000000000 +0100
+++ lib/wait-process.c  2009-03-01 18:09:48.000000000 +0100
@@ -269,7 +269,7 @@
       if (info.si_status == SIGPIPE && ignore_sigpipe)
        return 0;
 # endif
-      if (exit_on_error || !null_stderr)
+      if (exit_on_error || (!null_stderr && termsigp == NULL))
        error (exit_on_error ? EXIT_FAILURE : 0, 0,
               _("%s subprocess got fatal signal %d"),
               progname, info.si_status);
@@ -341,7 +341,7 @@
       if (WTERMSIG (status) == SIGPIPE && ignore_sigpipe)
        return 0;
 # endif
-      if (exit_on_error || !null_stderr)
+      if (exit_on_error || (!null_stderr && termsigp == NULL))
        error (exit_on_error ? EXIT_FAILURE : 0, 0,
               _("%s subprocess got fatal signal %d"),
               progname, (int) WTERMSIG (status));