threads / patch / 3630

patchimap-send: cleanup execl() call to use NULL sentinel instead of 0

Subject: [PATCH] imap-send: cleanup execl() call to use NULL sentinel instead of 0

## tl;dr

3 messages between Mar 11, 2006 and Mar 11, 2006. Diffs are folded; open one to read it.

replies: 2people: 2as markdown or json

Marco Roeland· Mar 11, 2006, 08:55 UTC · lore

Some versions of gcc check that calls to the exec() family have the proper sentinel for variadic calls. This should be (char *) NULL according to the man page. Although for all other purposes the 0 is equivalent, gcc nevertheless does emit a warning for 0 and not for NULL. This also makes the usage consistent throughout git.

The whitespace in function calls throughout imap-send.c has its own style, so I left it that way.

---

 imap-send.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

db1a0875cbc28970208e7a2fbb93d680d8ffe572

Show changes to imap-send.c +1 −1

diff --git a/imap-send.c b/imap-send.c
index fddaac0..203284d 100644
--- a/imap-send.c
+++ b/imap-send.c
@@ -945,7 +945,7 @@ imap_open_store( imap_server_conf_t *srv
 				_exit( 127 );
 			close( a[0] );
 			close( a[1] );
-			execl( "/bin/sh", "sh", "-c", srvc->tunnel, 0 );
+			execl( "/bin/sh", "sh", "-c", srvc->tunnel, NULL );
 			_exit( 127 );
 		}

-- 
1.2.4.ge29f
Marco Roeland

Morten Welinder· Mar 11, 2006, 14:01 UTC · re: Marco Roeland · lore

Re: [PATCH] imap-send: cleanup execl() call to use NULL sentinel instead of 0

If you're going to fix that, you should use (char *)NULL or (char *)0, just in case you end up on a machine where NULL doesn't a pointer type.

(Yup, NULL can be a null pointer without having pointer type.)

M.

Marco Roeland· Mar 11, 2006, 20:30 UTC · re: Morten Welinder · lore

Re: [PATCH] imap-send: cleanup execl() call to use NULL sentinel instead of 0

On Saturday March 11th 2006 Morten Welinder wrote:

Show 5 quoted lines

> If you're going to fix that, you should use (char *)NULL or
> (char *)0, just in case you end up on a machine where
> NULL doesn't a pointer type.
> 
> (Yup, NULL can be a null pointer without having pointer type.)

For gcc NULL is specifically always guaranteed to be a valid sentinel. And it was basically just about fixing the gcc warning, no pedantics intended! All other uses within git for the exec() family also use plain uncast NULL, which looks better anyway.

Strictly speaking you're probably right, but there's a chance that this will generate warnings on other compilers.

And if you should use a compiler with a weird notion of NULL, you're probably better off switching compilers immediately. ;-)

-- 
Marco Roeland