From: Craig A. Berry <craigberry@mac.com>
Date: Sat, 23 Mar 2002 23:23:00 +0000 (-0600)
Subject: extend use of home-grown kill() on VMS
X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=commitdiff_plain;h=05c058bc16a76532007427c68eaafb53a23230dc;p=p5sagit%2Fp5-mst-13.2.git

extend use of home-grown kill() on VMS
From: "Craig A. Berry" <craigberry@mac.com>
Message-Id: <a05101504b8c30e72f3e4@[172.16.52.1]>

p4raw-id: //depot/perl@15459
---

diff --git a/configure.com b/configure.com
index d7d0479..cfa695c 100644
--- a/configure.com
+++ b/configure.com
@@ -4943,24 +4943,29 @@ $   GOSUB compile
 $   nv_preserves_uv_bits = tmp
 $ ENDIF
 $!
-$ echo4 "Checking whether your kill() uses SYS$FORCEX..."
+$ echo4 "Checking if kill() uses SYS$FORCEX or can't be called from a signal handler..."
 $ kill_by_sigprc = "undef"
 $ OS
 $ WS "#include <stdio.h>"
 $ WS "#include <signal.h>"
 $ WS "#include <unistd.h>"
-$ WS "void handler(int s) { printf(""%d\n"",s); } "
+$ WS "void handler1(int s) { printf(""%d"",s); kill(getpid(),2); }"
+$ WS "void handler2(int s) { printf(""%d"",s); }"
 $ WS "main(){"
 $ WS "    printf(""0"");"
-$ WS "    signal(1,handler); kill(getpid(),1);"
+$ WS "    signal(1,handler1);"
+$ WS "    signal(2,handler2);"
+$ WS "    kill(getpid(),1);"
+$ WS "    sleep(1);"
+$ WS "    printf(""\n"");"
 $ WS "}"
 $ CS
 $ ON ERROR THEN CONTINUE
 $ GOSUB compile
-$ IF tmp .NES. "01"
+$ IF tmp .NES. "012"
 $ THEN 
-$   echo4 "Yes, it does." 
-$   echo4 "Checking whether we can use SYS$SIGPRC instead"
+$   echo4 "Yes, it has at least one of those limitations."
+$   echo4 "Checking whether we can use SYS$SIGPRC instead..."
 $   OS
 $   WS "#include <stdio.h>"
 $   WS "#include <lib$routines.h>"
diff --git a/vms/vms.c b/vms/vms.c
index 47716c3..4ae5541 100644
--- a/vms/vms.c
+++ b/vms/vms.c
@@ -1096,13 +1096,18 @@ Perl_my_sigaction (pTHX_ int sig, const struct sigaction* act,
 #ifdef KILL_BY_SIGPRC
 #include <errnodef.h>
 
-/* okay, this is some BLATENT hackery ... 
-   we use this if the kill() in the CRTL uses sys$forcex, causing the
+/* We implement our own kill() using the undocumented system service
+   sys$sigprc for one of two reasons:
+
+   1.) If the kill() in an older CRTL uses sys$forcex, causing the
    target process to do a sys$exit, which usually can't be handled 
    gracefully...certainly not by Perl and the %SIG{} mechanism.
 
-   Instead we use the (undocumented) system service sys$sigprc.
-   It has the same parameters as sys$forcex, but throws an exception
+   2.) If the kill() in the CRTL can't be called from a signal
+   handler without disappearing into the ether, i.e., the signal
+   it purportedly sends is never trapped. Still true as of VMS 7.3.
+
+   sys$sigprc has the same parameters as sys$forcex, but throws an exception
    in the target process rather than calling sys$exit.
 
    Note that distinguishing SIGSEGV from SIGBUS requires an extra arg