Re: Use `if (retval == -1)' instead of 'if (retval < 0)'
I don't see any problem.
ok yasuoka
On Wed, 14 Aug 2019 16:12:01 +0900 (JST)
Masato Asou wrote:
> Additional information.
>
> From: Masato Asou
> Subject: Use `if (retval == -1)' instead of 'if (retval < 0)'
> Date: Wed, 14 Aug 2019 13:42:13 +0900 (JST)
>
>> Hi tech,
>>
>> Use `if (retval == -1)' instead of 'if (retval < 0)' when check the
>> return value of system call.
>>
>> How about it?
>>
>> RCS file: /cvs/src/lib/libedit/readline.c,v
>> retrieving revision 1.28
>> diff -u -p -u -r1.28 readline.c
>> --- readline.c 28 Jun 2019 13:32:42 - 1.28
>> +++ readline.c 14 Aug 2019 04:38:55 -
>> @@ -2112,7 +2112,7 @@ _rl_event_read_char(EditLine *el, wchar_
>> return -1;
>> #endif
>>
>> - if (num_read < 0 && errno == EAGAIN)
>> + if (num_read == -1 && errno == EAGAIN)
>> continue;
>> if (num_read == 0)
>> continue;
>> --
>> ASOU Masato
>
> The valiable num_read has a return value of READ(2) system call as follows:
>
>2090 while (rl_event_hook) {
>2091
>2092 (*rl_event_hook)();
>2093
>2094 #if defined(FIONREAD)
>2095 if (ioctl(el->el_infd, FIONREAD, ) == -1)
>2096 return -1;
>2097 if (n)
>2098 num_read = read(el->el_infd, , 1);
>2099 else
>2100 num_read = 0;
>2101 #elif defined(F_SETFL) && defined(O_NDELAY)
>2102 if ((n = fcntl(el->el_infd, F_GETFL)) == -1)
>2103 return -1;
>2104 if (fcntl(el->el_infd, F_SETFL, n|O_NDELAY) ==
>-1)
>2105 return -1;
>2106 num_read = read(el->el_infd, , 1);
>2107 if (fcntl(el->el_infd, F_SETFL, n))
>2108 return -1;
>2109 #else
>2110 /* not non-blocking, but what you gonna do? */
>2111 num_read = read(el->el_infd, , 1);
>2112 return -1;
>2113 #endif
>2114
>2115 if (num_read < 0 && errno == EAGAIN)
>2116 continue;
>2117 if (num_read == 0)
>2118 continue;
>2119 break;
>2120 }
> --
> ASOU Masato
>
Re: Use `if (retval == -1)' instead of 'if (retval < 0)'
Additional information.
From: Masato Asou
Subject: Use `if (retval == -1)' instead of 'if (retval < 0)'
Date: Wed, 14 Aug 2019 13:42:13 +0900 (JST)
> Hi tech,
>
> Use `if (retval == -1)' instead of 'if (retval < 0)' when check the
> return value of system call.
>
> How about it?
>
> RCS file: /cvs/src/lib/libedit/readline.c,v
> retrieving revision 1.28
> diff -u -p -u -r1.28 readline.c
> --- readline.c 28 Jun 2019 13:32:42 - 1.28
> +++ readline.c 14 Aug 2019 04:38:55 -
> @@ -2112,7 +2112,7 @@ _rl_event_read_char(EditLine *el, wchar_
> return -1;
> #endif
>
> - if (num_read < 0 && errno == EAGAIN)
> + if (num_read == -1 && errno == EAGAIN)
> continue;
> if (num_read == 0)
> continue;
> --
> ASOU Masato
The valiable num_read has a return value of READ(2) system call as follows:
2090 while (rl_event_hook) {
2091
2092 (*rl_event_hook)();
2093
2094 #if defined(FIONREAD)
2095 if (ioctl(el->el_infd, FIONREAD, ) == -1)
2096 return -1;
2097 if (n)
2098 num_read = read(el->el_infd, , 1);
2099 else
2100 num_read = 0;
2101 #elif defined(F_SETFL) && defined(O_NDELAY)
2102 if ((n = fcntl(el->el_infd, F_GETFL)) == -1)
2103 return -1;
2104 if (fcntl(el->el_infd, F_SETFL, n|O_NDELAY) ==
-1)
2105 return -1;
2106 num_read = read(el->el_infd, , 1);
2107 if (fcntl(el->el_infd, F_SETFL, n))
2108 return -1;
2109 #else
2110 /* not non-blocking, but what you gonna do? */
2111 num_read = read(el->el_infd, , 1);
2112 return -1;
2113 #endif
2114
2115 if (num_read < 0 && errno == EAGAIN)
2116 continue;
2117 if (num_read == 0)
2118 continue;
2119 break;
2120 }
--
ASOU Masato
Use `if (retval == -1)' instead of 'if (retval < 0)'
Hi tech, Use `if (retval == -1)' instead of 'if (retval < 0)' when check the return value of system call. How about it? RCS file: /cvs/src/lib/libedit/readline.c,v retrieving revision 1.28 diff -u -p -u -r1.28 readline.c --- readline.c 28 Jun 2019 13:32:42 - 1.28 +++ readline.c 14 Aug 2019 04:38:55 - @@ -2112,7 +2112,7 @@ _rl_event_read_char(EditLine *el, wchar_ return -1; #endif - if (num_read < 0 && errno == EAGAIN) + if (num_read == -1 && errno == EAGAIN) continue; if (num_read == 0) continue; -- ASOU Masato
