diff mbox series

[v1,2/8] migration: Don't use '#' flag of printf format

Message ID 1602413863-19513-3-git-send-email-yubihong@huawei.com
State Superseded
Headers show
Series Fix some style problems in migration | expand

Commit Message

Bihong Yu Oct. 11, 2020, 10:57 a.m. UTC 
Signed-off-by:Bihong Yu <yubihong@huawei.com>
Reviewed-by: Chuan Zheng <zhengchuan@huawei.com>
Signed-off-by: Bihong Yu <yubihong@huawei.com>
---
 migration/block.c | 2 +-
 migration/ram.c   | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

Comments

Peter Maydell Oct. 11, 2020, 6:19 p.m. UTC | #1 
On Sun, 11 Oct 2020 at 14:52, Bihong Yu <yubihong@huawei.com> wrote:
> @@ -998,7 +998,7 @@ static int block_load(QEMUFile *f, void *opaque, int version_id)

>                     (addr == 100) ? '\n' : '\r');

>              fflush(stdout);

>          } else if (!(flags & BLK_MIG_FLAG_EOS)) {

> -            fprintf(stderr, "Unknown block migration flags: %#x\n", flags);

> +            fprintf(stderr, "Unknown block migration flags: %0x\n", flags);


This doesn't look right. "%#x" will print a number in hex with a leading '0x'.
To get the same effect without using "#" you need "0x%x" (that is,
the format string provides the 0x characters literally).
What you've written is '%0x", which is a format string where the '0' is
a request to print with zero padding (which is ignored since there's no
field width given), so the result is the same as if you'd just said '%x',
and there is no '0x' in the output.

$ cat /tmp/zz9.c
#include <stdio.h>
int main(void) {
  printf("%#x\n", 42);
  printf("%0x\n", 42);
  printf("0x%x\n", 42);
  return 0;
}
$ gcc -g -Wall -o /tmp/zz9 /tmp/zz9.c
$ /tmp/zz9
0x2a
2a
0x2a

>          default:

> -            error_report("Unknown combination of migration flags: %#x"

> +            error_report("Unknown combination of migration flags: %0x"

>                           " (postcopy mode)", flags);

>              ret = -EINVAL;

>              break;

> @@ -3576,7 +3576,7 @@ static int ram_load_precopy(QEMUFile *f)

>              if (flags & RAM_SAVE_FLAG_HOOK) {

>                  ram_control_load_hook(f, RAM_CONTROL_HOOK, NULL);

>              } else {

> -                error_report("Unknown combination of migration flags: %#x",

> +                error_report("Unknown combination of migration flags: %0x",

>                               flags);

>                  ret = -EINVAL;

>              }


These two similarly should be "0x%x".

thanks
-- PMM
Bihong Yu Oct. 12, 2020, 12:45 p.m. UTC | #2 
Thank you for your review. OK,I have fixed the problem in v2.

On 2020/10/12 2:19, Peter Maydell wrote:
> On Sun, 11 Oct 2020 at 14:52, Bihong Yu <yubihong@huawei.com> wrote:

>> @@ -998,7 +998,7 @@ static int block_load(QEMUFile *f, void *opaque, int version_id)

>>                     (addr == 100) ? '\n' : '\r');

>>              fflush(stdout);

>>          } else if (!(flags & BLK_MIG_FLAG_EOS)) {

>> -            fprintf(stderr, "Unknown block migration flags: %#x\n", flags);

>> +            fprintf(stderr, "Unknown block migration flags: %0x\n", flags);

> 

> This doesn't look right. "%#x" will print a number in hex with a leading '0x'.

> To get the same effect without using "#" you need "0x%x" (that is,

> the format string provides the 0x characters literally).

> What you've written is '%0x", which is a format string where the '0' is

> a request to print with zero padding (which is ignored since there's no

> field width given), so the result is the same as if you'd just said '%x',

> and there is no '0x' in the output.

> 

> $ cat /tmp/zz9.c

> #include <stdio.h>

> int main(void) {

>   printf("%#x\n", 42);

>   printf("%0x\n", 42);

>   printf("0x%x\n", 42);

>   return 0;

> }

> $ gcc -g -Wall -o /tmp/zz9 /tmp/zz9.c

> $ /tmp/zz9

> 0x2a

> 2a

> 0x2a

> 

>>          default:

>> -            error_report("Unknown combination of migration flags: %#x"

>> +            error_report("Unknown combination of migration flags: %0x"

>>                           " (postcopy mode)", flags);

>>              ret = -EINVAL;

>>              break;

>> @@ -3576,7 +3576,7 @@ static int ram_load_precopy(QEMUFile *f)

>>              if (flags & RAM_SAVE_FLAG_HOOK) {

>>                  ram_control_load_hook(f, RAM_CONTROL_HOOK, NULL);

>>              } else {

>> -                error_report("Unknown combination of migration flags: %#x",

>> +                error_report("Unknown combination of migration flags: %0x",

>>                               flags);

>>                  ret = -EINVAL;

>>              }

> 

> These two similarly should be "0x%x".

> 

> thanks

> -- PMM

> .

>
diff mbox series

Patch

diff --git a/migration/block.c b/migration/block.c
index 4b8576b..399dfb8 100644
--- a/migration/block.c
+++ b/migration/block.c
@@ -998,7 +998,7 @@  static int block_load(QEMUFile *f, void *opaque, int version_id)
                    (addr == 100) ? '\n' : '\r');
             fflush(stdout);
         } else if (!(flags & BLK_MIG_FLAG_EOS)) {
-            fprintf(stderr, "Unknown block migration flags: %#x\n", flags);
+            fprintf(stderr, "Unknown block migration flags: %0x\n", flags);
             return -EINVAL;
         }
         ret = qemu_file_get_error(f);
diff --git a/migration/ram.c b/migration/ram.c
index 433489d..59bdd15 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -3298,7 +3298,7 @@  static int ram_load_postcopy(QEMUFile *f)
             multifd_recv_sync_main();
             break;
         default:
-            error_report("Unknown combination of migration flags: %#x"
+            error_report("Unknown combination of migration flags: %0x"
                          " (postcopy mode)", flags);
             ret = -EINVAL;
             break;
@@ -3576,7 +3576,7 @@  static int ram_load_precopy(QEMUFile *f)
             if (flags & RAM_SAVE_FLAG_HOOK) {
                 ram_control_load_hook(f, RAM_CONTROL_HOOK, NULL);
             } else {
-                error_report("Unknown combination of migration flags: %#x",
+                error_report("Unknown combination of migration flags: %0x",
                              flags);
                 ret = -EINVAL;
             }