char *与const char * [英] char * vs. const char *
问题描述
嗨伙计
声称符合标准的C编译器是合法的
（c89）对以下内容发出错误：
char * foo（const char * s）
{
const char * s;
for（s = src; * s&&！（（（unsigned char）s [0]）& 0x80）; s ++）
if（* s = = c）
返回s;
....
}
编译时遇到2个错误：
错误（212）：返回值类型与函数类型不匹配
error（611）：类型为const char *的值无法分配给实体
类型为char *
我会理解警告，但是出错了吗？
再见，Jojo
Hi folks
Is it legal for a C compiler that claims to be conforming to the standard
(c89) to issue an error on the following:
char *foo(const char *s)
{
const char *s;
for (s = src; *s && !(((unsigned char)s[0]) & 0x80); s++)
if (*s == c)
return s;
....
}
I get 2 errors when compiling this:
error(212): return value type does not match the function type
error(611): a value of type "const char *" cannot be assigned to an entity
of type "char *"
I''d understand a warning, but an error?
Bye, Jojo
推荐答案
Joachim Schmitz写道：
Joachim Schmitz wrote:
对C来说是否合法声称符合标准的编译器（c89）在以下内容上发出错误：
是的。事实上，一个符合标准的编译器/有义务/诊断这个
代码。
char * foo（const char * s）
const char * s;
[...]
我会理解一个警告，但是出错了吗？
Is it legal for a C compiler that claims to be conforming to the standard
(c89) to issue an error on the following:
Yes. In fact, a conforming compiler is /obliged/ to diagnose this
code.
char *foo(const char *s)
{
const char *s; [...]
I''d understand a warning, but an error?
没有C89中警告和错误之间的区别：
标准要求诊断和诊断。是针对某些违规行为发出的。在发出这样的诊断后，编译器没有继续翻译的义务。
Jeremy。
There''s no distinction between warnings and errors in C89: the
standard requires that "diagnostics" are issued for certain
violations. After such a diagnostic has been issued the compiler is
under no obligation to continue translation.
Jeremy.
嗨Jeremy
" Jeremy Yallop" < JE **** @ jdyallop.freeserve.co.uk>在消息中写道
news：sl ******************* @ maka.cl.cam.ac.uk ...
Hi Jeremy
"Jeremy Yallop" <je****@jdyallop.freeserve.co.uk> wrote in message
news:sl*******************@maka.cl.cam.ac.uk...
Joachim Schmitz写道：
Joachim Schmitz wrote:
声称符合
标准（c89）的C编译器对以下内容发出错误是否合法：
是。实际上，符合标准的编译器/有义务/诊断这个代码。
Is it legal for a C compiler that claims to be conforming to the standard (c89) to issue an error on the following:
Yes. In fact, a conforming compiler is /obliged/ to diagnose this
code.
char * foo（const char * s）
const char * s;
char *foo(const char *s)
{
const char *s;
[...]
[...]
我会理解一个警告，但是出错？
I''d understand a warning, but an error?
<在C89中，警告和错误之间没有区别：
标准要求诊断和诊断。是为了某些违法行为而发出的。在发出这样的诊断之后，编译器没有义务继续翻译。
There''s no distinction between warnings and errors in C89: the
standard requires that "diagnostics" are issued for certain
violations. After such a diagnostic has been issued the compiler is
under no obligation to continue translation.
谢谢，
好吧，不幸的是Samba代码充满了这些东西，我必须在所有地方插入
（char *）来编译...
如果允许编译器对此嗤之以鼻，这将是Samba的一个错误，我会
报告它。否则我会把它报告为对我们的c89的错误...
Jeremy。
Thanks,
Well, unfortunaly the Samba code is full of such things and I have to insert
(char *) all over the place to get it compiled...
If a compiler is allowd to choke on this, it''d be a bug in Samba and I''ll
report it as such. Otherwise I''d report it as a bug against our c89...
Jeremy.
再见，Jojo
Bye, Jojo
Joachim Schmitz< no *********** @ hp.com>写道：
Joachim Schmitz <no***********@hp.com> wrote:
嗨伙计
对于声称符合标准的C编译器（c89）是否合法，以便对以下内容发出错误：
char * foo（const char * s）
{
const char * s;
for（s = src; * s&&！（（（unsigned char）s [0] ）& 0x80）; s ++）
if（* s == c）
return s;
...
}
编译时遇到2个错误：
error（212）：返回值类型与函数类型不匹配
error（611） ：类型为const char *的值不能分配给类型为char *的实体
我会理解一个警告，但是出错了吗？
Hi folks Is it legal for a C compiler that claims to be conforming to the standard
(c89) to issue an error on the following: char *foo(const char *s)
{
const char *s;
for (s = src; *s && !(((unsigned char)s[0]) & 0x80); s++) if (*s == c) return s; ... } I get 2 errors when compiling this: error(212): return value type does not match the function type error(611): a value of type "const char *" cannot be assigned to an entity
of type "char *" I''d understand a warning, but an error?
在这种情况下，编译器有义务发出诊断信息。是否
这是一个警告或错误是没有密切关系的标准
。
-
Alex Monjushko（mo*******@hotmail.com）
The compiler is obligated to emit a diagnostic in this case. Whether
it is a warning or an error is not germane as far as the standard is
concerned.
--
Alex Monjushko (mo*******@hotmail.com)
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