[CC += linux-man@]
Hello Jan,
There are many ideas in this mail, and it might have been a little
easier to split them out into pieces. I'll reply to some of them here.
On Fri, Feb 11, 2011 at 11:56 PM, Jan Engelhardt <jengelh@xxxxxxxxxx> wrote:
>
>
> I have a few manpage updates further below.
>
>
> Other things still looming:
>
> rtime.3 calls ctime((time_t *)&time1.tv_sec), but this is fatal, since
> time1.tv_sec is of type uint32_t while time_t can be of different size
> (and in fact, is so on glibc-x86_64).
Ye. I applied this patch:
--- a/man3/rtime.3
+++ b/man3/rtime.3
@@ -111,8 +111,10 @@ main(void)
ret = rtime(&name, &time1, use_tcp ? NULL : &timeout);
if (ret < 0)
perror("rtime error");
- else
- printf("%s\\n", ctime((time_t *) &time1.tv_sec));
+ else {
+ time_t t = time1.tv_sec;
+ printf("%s\\n", ctime(&t));
+ }
exit(EXIT_SUCCESS);
}
> ---
>
>> /* Writing: cosine = (double (*)(double)) dlsym(handle, "cos");
>> would seem more natural, but the C99 standard leaves
>> casting from "void *" to a function pointer undefined.
>
> Which is ok, given dlopen isn't part of C99 anyway.
>
> A derivative standard of C, or an implementation thereof, like the
> gcc-POSIX pair, may choose to make it defined to explicitly make dlsym
> work within the given implementation.
>
>
>>*(void **) (&cosine) = dlsym(handle, "cos");
>>.\" But in fact "gcc -O2 -Wall" will complain about the preceding cast.
>
> And it does so rightfully. Now I don't claim to grasp strict-aliasing
> completely - I better just avoid it, and subsequently, constructs like
> *(void **)&x, because they, in themselves, are really unsafe. It's like
> writing
>
> uint8_t x;
> *(uint16_t *)&x = dlsym
>
> which is undefined behavior too. IMO,
>
> cosine = dlsym(...)
>
> is the much lesser evil of the two (still considering only POSIX, not
> C99), because 1. you don't write beyond the end of the object, 2. it
> will also work when sizeof(funcptr) <= sizeof(void *), 3. cast is
> avoided, implicit truncation can take place.
>
> .oO(Having worked with DOS far and near stuff does pay off at times..)
Could you take this last piece to a separate mail thread please?
> ----
>
> The following changes since commit 4fa455f024eb453a2e8768d838d2fc016b56b291:
>
> Changes.old: spfix (2010-12-05 16:10:07 +0100)
>
> are available in the git repository at:
> git://dev.medozas.de/man-pages master
Lacking the patch, which disappeared because I was slow to react, I
did some inspection, and tried to find the cases you refer to below.
My results, and a patch, below.
> Jan Engelhardt (4):
> all: remove redundant casts
> pthread_getattr_np.3: add a required cast
> hsearch.3: add a required cast
> bsearch.3, rtime.3: add const qualifiers
>
> man2/getdents.2 | 2 +-
Found, I think.
> man2/select_tut.2 | 2 +-
Found, I think.
> man3/argz_add.3 | 2 +-
Not found. If you meant the "(char *) 0" cast, I believe that's incorrect.
> man3/atof.3 | 2 +-
Found.
> man3/atoi.3 | 2 +-
Found.
> man3/bsearch.3 | 6 +++---
Not found (you suggested to add "const" somewhere)
> man3/hsearch.3 | 2 +-
Not found. You suggested "add a required cast".
> man3/pthread_create.3 | 2 +-
Found, I think.
> man3/pthread_getattr_np.3 | 2 +-
Not found. You said "add a required cast".
> man3/pthread_sigmask.3 | 4 ++--
Found, I think.
> man3/rtime.3 | 13 +++++++------
Found, I think.
> man3/setbuf.3 | 2 +-
Found.
> man3/tsearch.3 | 4 ++--
Found, I think.
> man7/netlink.7 | 6 +++---
Found, I think. (3 instances, right?)
> 14 files changed, 26 insertions(+), 25 deletions(-)
I applied the patch below to remove the unneeded casts.
Cheers,
Michael
--- a/man2/getdents.2
+++ b/man2/getdents.2
@@ -24,7 +24,7 @@
.\" Modified 22 July 1995 by Michael Chastain <mec@xxxxxxxxxxxxxxxxx>:
.\" Derived from 'readdir.2'.
.\" Modified Tue Oct 22 08:11:14 EDT 1996 by Eric S. Raymond <esr@xxxxxxxxxxx>
-.TH GETDENTS 2 2012-07-13 "Linux" "Linux Programmer's Manual"
+.TH GETDENTS 2 2012-08-03 "Linux" "Linux Programmer's Manual"
.SH NAME
getdents \- get directory entries
.SH SYNOPSIS
@@ -268,7 +268,7 @@ main(int argc, char *argv[])
(d_type == DT_BLK) ? "block dev" :
(d_type == DT_CHR) ? "char dev" : "???");
printf("%4d %10lld %s\\n", d\->d_reclen,
- (long long) d\->d_off, (char *) d->d_name);
+ (long long) d\->d_off, d->d_name);
bpos += d\->d_reclen;
}
}
diff --git a/man2/select_tut.2 b/man2/select_tut.2
index 17c74ac..d9fb610 100644
--- a/man2/select_tut.2
+++ b/man2/select_tut.2
@@ -27,7 +27,7 @@
.\" various other changes
.\" 2008-01-26, mtk, substantial changes and rewrites
.\"
-.TH SELECT_TUT 2 2010-06-10 "Linux" "Linux Programmer's Manual"
+.TH SELECT_TUT 2 2012-08-03 "Linux" "Linux Programmer's Manual"
.SH NAME
select, pselect, FD_CLR, FD_ISSET, FD_SET, FD_ZERO \-
synchronous I/O multiplexing
@@ -561,7 +561,7 @@ listen_socket(int listen_port)
}
yes = 1;
if (setsockopt(s, SOL_SOCKET, SO_REUSEADDR,
- (char *) &yes, sizeof(yes)) == \-1) {
+ &yes, sizeof(yes)) == \-1) {
perror("setsockopt");
close(s);
return \-1;
diff --git a/man3/atof.3 b/man3/atof.3
index f5f53ea..029f915 100644
--- a/man3/atof.3
+++ b/man3/atof.3
@@ -26,7 +26,7 @@
.\" 386BSD man pages
.\" Modified Mon Mar 29 22:39:24 1993, David Metcalfe
.\" Modified Sat Jul 24 21:39:22 1993, Rik Faith (faith@xxxxxxxxxx)
-.TH ATOF 3 1993-03-29 "GNU" "Linux Programmer's Manual"
+.TH ATOF 3 2012-08-03 "GNU" "Linux Programmer's Manual"
.SH NAME
atof \- convert a string to a double
.SH SYNOPSIS
@@ -44,7 +44,7 @@ pointed to by \fInptr\fP to
The behavior is the same as
.sp
.in +4n
-strtod(nptr, (char **) NULL);
+strtod(nptr, NULL);
.in
.sp
except that
diff --git a/man3/atoi.3 b/man3/atoi.3
index 31c35ca..41a4c59 100644
--- a/man3/atoi.3
+++ b/man3/atoi.3
@@ -28,7 +28,7 @@
.\" Modified Sat Jul 24 21:38:42 1993, Rik Faith (faith@xxxxxxxxxx)
.\" Modified Sun Dec 17 18:35:06 2000, Joseph S. Myers
.\"
-.TH ATOI 3 2010-09-20 "GNU" "Linux Programmer's Manual"
+.TH ATOI 3 2012-08-03 "GNU" "Linux Programmer's Manual"
.SH NAME
atoi, atol, atoll, atoq \- convert a string to an integer
.SH SYNOPSIS
@@ -68,7 +68,7 @@ pointed to by \fInptr\fP to
The behavior is the same as
.sp
.in +4n
-strtol(nptr, (char **) NULL, 10);
+strtol(nptr, NULL, 10);
.in
.sp
except that
diff --git a/man3/pthread_create.3 b/man3/pthread_create.3
index 66190bb..42df859 100644
--- a/man3/pthread_create.3
+++ b/man3/pthread_create.3
@@ -21,7 +21,7 @@
.\" Formatted or processed versions of this manual, if unaccompanied by
.\" the source, must acknowledge the copyright and authors of this work.
.\"
-.TH PTHREAD_CREATE 3 2012-03-15 "Linux" "Linux Programmer's Manual"
+.TH PTHREAD_CREATE 3 2012-08-03 "Linux" "Linux Programmer's Manual"
.SH NAME
pthread_create \- create a new thread
.SH SYNOPSIS
@@ -265,7 +265,7 @@ struct thread_info { /* Used as argument to
thread_start() */
static void *
thread_start(void *arg)
{
- struct thread_info *tinfo = (struct thread_info *) arg;
+ struct thread_info *tinfo = arg;
char *uargv, *p;
printf("Thread %d: top of stack near %p; argv_string=%s\\n",
diff --git a/man3/pthread_sigmask.3 b/man3/pthread_sigmask.3
index ffdc6ca..de78dac 100644
--- a/man3/pthread_sigmask.3
+++ b/man3/pthread_sigmask.3
@@ -21,7 +21,7 @@
.\" Formatted or processed versions of this manual, if unaccompanied by
.\" the source, must acknowledge the copyright and authors of this work.
.\"
-.TH PTHREAD_SIGMASK 3 2011-10-16 "Linux" "Linux Programmer's Manual"
+.TH PTHREAD_SIGMASK 3 2012-08-03 "Linux" "Linux Programmer's Manual"
.SH NAME
pthread_sigmask \- examine and change mask of blocked signals
.SH SYNOPSIS
@@ -92,7 +92,7 @@ Signal handling thread got signal 10
static void *
sig_thread(void *arg)
{
- sigset_t *set = (sigset_t *) arg;
+ sigset_t *set = arg;
int s, sig;
for (;;) {
diff --git a/man3/rtime.3 b/man3/rtime.3
index e19429e..c37672a 100644
--- a/man3/rtime.3
+++ b/man3/rtime.3
@@ -5,7 +5,7 @@
.\"
.\" Slightly polished, aeb, 2003-04-06
.\"
-.TH RTIME 3 2010-02-25 "GNU" "Linux Programmer's Manual"
+.TH RTIME 3 2012-08-03 "GNU" "Linux Programmer's Manual"
.SH NAME
rtime \- get time from a remote machine
.SH SYNOPSIS
@@ -103,10 +103,10 @@ main(void)
struct hostent *hent;
int ret;
- memset((char *) &name, 0, sizeof(name));
+ memset(&name, 0, sizeof(name));
sethostent(1);
hent = gethostbyname(servername);
- memcpy((char *) &name.sin_addr, hent\->h_addr, hent\->h_length);
+ memcpy(&name.sin_addr, hent\->h_addr, hent\->h_length);
ret = rtime(&name, &time1, use_tcp ? NULL : &timeout);
if (ret < 0)
diff --git a/man3/setbuf.3 b/man3/setbuf.3
index b9d41a9..49fca4d 100644
--- a/man3/setbuf.3
+++ b/man3/setbuf.3
@@ -43,7 +43,7 @@
.\" Correction, 2000-03-03, Andreas Jaeger <aj@xxxxxxx>
.\" Added return value for setvbuf, aeb,
.\"
-.TH SETBUF 3 2008-06-26 "Linux" "Linux Programmer's Manual"
+.TH SETBUF 3 2012-08-03 "Linux" "Linux Programmer's Manual"
.SH NAME
setbuf, setbuffer, setlinebuf, setvbuf \- stream buffering operations
.SH SYNOPSIS
@@ -145,7 +145,7 @@ The
function is exactly equivalent to the call:
.PP
.in +4n
-setvbuf(stream, (char *) NULL, _IOLBF, 0);
+setvbuf(stream, NULL, _IOLBF, 0);
.in
.SH "RETURN VALUE"
The function
diff --git a/man3/tsearch.3 b/man3/tsearch.3
index bb96740..daedc88 100644
--- a/man3/tsearch.3
+++ b/man3/tsearch.3
@@ -21,7 +21,7 @@
.\" Formatted or processed versions of this manual, if unaccompanied by
.\" the source, must acknowledge the copyright and authors of this work.
.\"
-.TH TSEARCH 3 2012-06-11 "GNU" "Linux Programmer's Manual"
+.TH TSEARCH 3 2012-08-03 "GNU" "Linux Programmer's Manual"
.SH NAME
tsearch, tfind, tdelete, twalk, tdestroy \- manage a binary tree
.SH SYNOPSIS
@@ -273,7 +273,7 @@ main(void)
srand(time(NULL));
for (i = 0; i < 12; i++) {
- ptr = (int *) xmalloc(sizeof(int));
+ ptr = xmalloc(sizeof(int));
*ptr = rand() & 0xff;
val = tsearch((void *) ptr, &root, compare);
if (val == NULL)
diff --git a/man7/netlink.7 b/man7/netlink.7
index 2b60fe3..35016a2 100644
--- a/man7/netlink.7
+++ b/man7/netlink.7
@@ -417,10 +417,10 @@ in order to reliably track acknowledgements.
.nf
struct nlmsghdr *nh; /* The nlmsghdr with payload to send. */
struct sockaddr_nl sa;
-struct iovec iov = { (void *) nh, nh\->nlmsg_len };
+struct iovec iov = { nh, nh\->nlmsg_len };
struct msghdr msg;
-msg = { (void *)&sa, sizeof(sa), &iov, 1, NULL, 0, 0 };
+msg = { &sa, sizeof(sa), &iov, 1, NULL, 0, 0 };
memset(&sa, 0, sizeof(sa));
sa.nl_family = AF_NETLINK;
nh\->nlmsg_pid = 0;
@@ -443,7 +443,7 @@ struct sockaddr_nl sa;
struct msghdr msg;
struct nlmsghdr *nh;
-msg = { (void *)&sa, sizeof(sa), &iov, 1, NULL, 0, 0 };
+msg = { &sa, sizeof(sa), &iov, 1, NULL, 0, 0 };
len = recvmsg(fd, &msg, 0);
for (nh = (struct nlmsghdr *) buf; NLMSG_OK (nh, len);
--
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Author of "The Linux Programming Interface"; http://man7.org/tlpi/
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