Add VMS support for pcre2grep callout of an external program.

ChangeLog

@@ -80,6 +80,9 @@ that do not support fork().
 19. Fix two instances of <= 0 being applied to unsigned integers (the VMS 
 compiler complains).
 
+20. Added "fork" support for VMS to pcre2grep, for running an external program 
+via a string callout.
+
 
 Version 10.32 10-September-2018
 -------------------------------

doc/pcre2grep.1

@@ -1,4 +1,4 @@
-.TH PCRE2GREP 1 "17 November 2018" "PCRE2 10.33"
+.TH PCRE2GREP 1 "24 November 2018" "PCRE2 10.33"
 .SH NAME
 pcre2grep - a grep with Perl-compatible regular expressions.
 .SH SYNOPSIS
@@ -778,9 +778,13 @@ only callouts with string arguments are useful.
 .SS "Calling external programs or scripts"
 .rs
 .sp
-This facility can be independently disabled when \fBpcre2grep\fP is built. If
+This facility can be independently disabled when \fBpcre2grep\fP is built. It 
-the callout string does not start with a pipe (vertical bar) character, it is
+is supported for Windows, where a call to \fB_spawnvp()\fP is used, for VMS, 
-parsed into a list of substrings separated by pipe characters. The first
+where \fBlib$spawn()\fP is used, and for any other Unix-like environment where
+\fBfork()\fP and \fBexecv()\fP are available.
+.P
+If the callout string does not start with a pipe (vertical bar) character, it
+is parsed into a list of substrings separated by pipe characters. The first
 substring must be an executable name, with the following substrings specifying
 arguments:
 .sp
@@ -806,7 +810,7 @@ a single dollar and $| is replaced by a pipe character. Here is an example:
     Arg1: [1] [234] [4] Arg2: |1| ()
     12345
 .sp
-The parameters for the \fBexecv()\fP system call that is used to run the
+The parameters for the system call that is used to run the
 program or script are zero-terminated strings. This means that binary zero
 characters in the callout argument will cause premature termination of their
 substrings, and therefore should not be present. Any syntax errors in the
@@ -880,6 +884,6 @@ Cambridge, England.
 .rs
 .sp
 .nf
-Last updated: 17 November 2018
+Last updated: 24 November 2018
 Copyright (c) 1997-2018 University of Cambridge.
 .fi

src/pcre2grep.c

@@ -68,6 +68,12 @@ POSSIBILITY OF SUCH DAMAGE.
 #undef WIN32
 #endif
 
+#ifdef __VMS
+#include clidef
+#include descrip
+#include lib$routines
+#endif
+
 #ifdef WIN32
 #include <io.h>                /* For _setmode() */
 #include <fcntl.h>             /* For _O_BINARY */
@@ -573,8 +579,6 @@ status of 1, which is not helpful. To help with this problem, define a symbol
 therein. */
 
 #ifdef __VMS
-#include descrip
-#include lib$routines
   char val_buf[4];
   $DESCRIPTOR(sym_nam, "PCRE2GREP_RC");
   $DESCRIPTOR(sym_val, val_buf);
@@ -2285,11 +2289,34 @@ while (length > 0)
 *argsptr++ = '\0';
 *argsvectorptr = NULL;
 
+/* Running an external command is system-dependent. Handle Windows and VMS as
+necessary, otherwise assume fork(). */
+
 #ifdef WIN32
 result = _spawnvp(_P_WAIT, argsvector[0], (const char * const *)argsvector);
-#else
-pid = fork();
 
+#elif defined __VMS
+  {
+  char cmdbuf[500];
+  short i = 0;
+  int flags = CLI$M_NOCLISYM|CLI$M_NOLOGNAM|CLI$M_NOKEYPAD, status, retstat;
+  $DESCRIPTOR(cmd, cmdbuf);
+
+  cmdbuf[0] = 0;
+  while (argsvector[i])
+  {
+    strcat(cmdbuf, argsvector[i]);
+    strcat(cmdbuf, " ");
+    i++;
+  }
+  cmd.dsc$w_length = strlen(cmdbuf) - 1;
+  status = lib$spawn(&cmd, 0,0, &flags, 0,0, &retstat);
+  if (!(status & 1)) result = 0;
+  else result = retstat & 1 ? 0 : 1;
+  }
+
+#else  /* Neither Windows nor VMS */
+pid = fork();
 if (pid == 0)
   {
   (void)execv(argsvector[0], argsvector);
@@ -2298,7 +2325,7 @@ if (pid == 0)
   }
 else if (pid > 0)
   (void)waitpid(pid, &result, 0);
-#endif
+#endif  /* End Windows/VMS/other handling */
 
 free(args);
 free(argsvector);