win32: user defined shell

This patch replaces the patch in win32.3 in the gnat collection.

The reasons for reworking that patch should be evident from
reading the patch below.

p5p-msgid: 199705291339.JAA21682@aatma.engin.umich.edu

diff --git a/pod/perlrun.pod b/pod/perlrun.pod
index c4679e1..de7116d 100644 (file)
--- a/pod/perlrun.pod
+++ b/pod/perlrun.pod
@@ -567,6 +567,17 @@ The command used to load the debugger code.  The default is:
 
        BEGIN { require 'perl5db.pl' }
 
+=item PERL5SHELL (specific to WIN32 port)
+
+May be set to an alternative shell that perl must use internally for
+executing "backtick" commands or system().  Perl doesn't use COMSPEC
+for this purpose because COMSPEC has a high degree of variability
+among users, leading to portability concerns.  Besides, perl can use
+a shell that may not be fit for interactive use, and setting COMSPEC
+to such a shell may interfere with the proper functioning of other
+programs (which usually look in COMSPEC to find a shell fit for
+interactive use).
+
 =item PERL_DEBUG_MSTATS
 
 Relevant only if your perl executable was built with B<-DDEBUGGING_MSTATS>,

diff --git a/win32/win32.c b/win32/win32.c
index 7fb0416..57e90a2 100644 (file)
--- a/win32/win32.c
+++ b/win32/win32.c
@@ -317,18 +317,19 @@ IdOS(void)
 static char *
 GetShell(void)
 {
-    static char* szWin95ShellEntry = "Win95Shell";
-    static char* szWin95DefaultShell = "Cmd32.exe";
-    static char* szWinNTDefaultShell = "cmd.exe";
-   
     if (!ProbeEnv) {
+       char* defaultshell = (IsWinNT() ? "cmd.exe" : "command.com");
+       /* we don't use COMSPEC here for two reasons:
+        *  1. the same reason perl on UNIX doesn't use SHELL--rampant and
+        *     uncontrolled unportability of the ensuing scripts.
+        *  2. PERL5SHELL could be set to a shell that may not be fit for
+        *     interactive use (which is what most programs look in COMSPEC
+        *     for).
+        */
+       char *usershell = getenv("PERL5SHELL");  
+
        ProbeEnv = TRUE;
-       if (IsWin95()) {
-           strcpy(szShellPath, szWin95DefaultShell);
-       }
-       else {
-           strcpy(szShellPath, szWinNTDefaultShell);
-       }
+       strcpy(szShellPath, usershell ? usershell : defaultshell);
     }
     return szShellPath;
 }