avoid select() on windows destroying errno (used to typically

always sets it to EINVAL due to the way it maps the FD_SETs)

p4raw-id: //depot/perl@19533

diff --git a/win32/win32sck.c b/win32/win32sck.c
index cd537b3..d89c306 100644 (file)
--- a/win32/win32sck.c
+++ b/win32/win32sck.c
@@ -291,7 +291,7 @@ win32_select(int nfds, Perl_fd_set* rd, Perl_fd_set* wr, Perl_fd_set* ex, const
     int r;
 #ifdef USE_SOCKETS_AS_HANDLES
     Perl_fd_set dummy;
-    int i, fd;
+    int i, fd, save_errno;
     FD_SET nrd, nwr, nex, *prd, *pwr, *pex;
 
     /* winsock seems incapable of dealing with all three null fd_sets,
@@ -333,7 +333,9 @@ win32_select(int nfds, Perl_fd_set* rd, Perl_fd_set* wr, Perl_fd_set* ex, const
            FD_SET(fd, &nex);
     }
 
+    errno = save_errno;
     SOCKET_TEST_ERROR(r = select(nfds, prd, pwr, pex, timeout));
+    save_errno = errno;
 
     for (i = 0; i < nfds; i++) {
        fd = TO_SOCKET(i);
@@ -344,6 +346,7 @@ win32_select(int nfds, Perl_fd_set* rd, Perl_fd_set* wr, Perl_fd_set* ex, const
        if (PERL_FD_ISSET(i,ex) && !FD_ISSET(fd, &nex))
            PERL_FD_CLR(i,ex);
     }
+    errno = save_errno;
 #else
     SOCKET_TEST_ERROR(r = select(nfds, rd, wr, ex, timeout));
 #endif