Problem with braces in C

Problem with braces in C

[Burkhard Schultheis]

We have overtaken a C program package with a horrible huge C function in 
it (about 3500 lines of code in a single function!). Now Emacs 21.3.1 
shows unbalanced braces at the first 5 opening braces. But:

1.) The code compiles without problems
2.) We can jump with match-paren to the corresponding closing braces
3.) A double-click with the left mouse button jumps to the corresponding 
braces, too.
4.) indent-region indents perfectly the whole function.

Is it a known bug?

Thank you in advance!

Regards
Burkhard

Re: Problem with braces in C

[Scott Frazer]

Burkhard Schultheis wrote:
> We have overtaken a C program package with a horrible huge C function in 
> it (about 3500 lines of code in a single function!). Now Emacs 21.3.1 
> shows unbalanced braces at the first 5 opening braces. But:
> 
> 1.) The code compiles without problems
> 2.) We can jump with match-paren to the corresponding closing braces
> 3.) A double-click with the left mouse button jumps to the corresponding 
> braces, too.
> 4.) indent-region indents perfectly the whole function.
> 
> Is it a known bug?
> 

Try setting blink-matching-paren-distance to nil.

Scott

Re: Problem with braces in C

[Burkhard Schultheis]

Am 05.11.2009 19:06, schrieb Scott Frazer:
> Burkhard Schultheis wrote:
>> We have overtaken a C program package with a horrible huge C function
>> in it (about 3500 lines of code in a single function!). Now Emacs
>> 21.3.1 shows unbalanced braces at the first 5 opening braces. But:
>>
>> 1.) The code compiles without problems
>> 2.) We can jump with match-paren to the corresponding closing braces
>> 3.) A double-click with the left mouse button jumps to the
>> corresponding braces, too.
>> 4.) indent-region indents perfectly the whole function.
>>
>> Is it a known bug?
>>
>
> Try setting blink-matching-paren-distance to nil.

Thank you very much. Now it works as it should.

Regards
Burkhard

Re: Problem with braces in C

[despen]

Burkhard Schultheis <burkhard.schultheis@web.de> writes:

> We have overtaken a C program package with a horrible huge C function
> in it (about 3500 lines of code in a single function!). Now Emacs
> 21.3.1 shows unbalanced braces at the first 5 opening braces. But:
>
> 1.) The code compiles without problems
> 2.) We can jump with match-paren to the corresponding closing braces
> 3.) A double-click with the left mouse button jumps to the
> corresponding braces, too.
> 4.) indent-region indents perfectly the whole function.
>
> Is it a known bug?

Are there #if/#ifdef around some parts of the braces?

That's what usually gets me.
In C code, it's better to use "if" and let the
optimizer make the choices.  It doesn't confuse Emacs
and it's more readable.

Re: Problem with braces in C

[Burkhard Schultheis]

Am 05.11.2009 19:47, schrieb despen@verizon.net:
>
> Are there #if/#ifdef around some parts of the braces?

No. ;-)

Regards
Burkhard

Re: Problem with braces in C

[Colin S. Miller]

Burkhard Schultheis wrote:
> Am 05.11.2009 19:47, schrieb despen@verizon.net:
>>
>> Are there #if/#ifdef around some parts of the braces?
> 
> No. ;-)
> 
> Regards
> Burkhard


Hmm.
The normal way of spooking paren-mode is to do something like this, as Scott suggested

#if DEBUG
void myFunc(int a, float b, const char *FILE, int LINE) {
#else
void myFunc(int a, float b) {
#endif

replacing with

#if DEBUG
void myFunc(int a, float b, const char *FILE, int LINE)
#else
void myFunc(int a, float b)
#endif
{

will fix it.

As paren mode looks at the file before it pre-processed, it needs the brackets to match literally.
Other things that can spook it include (nb. brackets include {} () [] - if the order doesn't match, then
paren-mode can get confused)

1) Brackets in C++ style // comments, if C mode doesn't define these as a comment.
2) Brackets in pre-processor expansions.


Try placing the cursor immediately after the last curly bracket, and pressing
C-M-p. This will jump the cursor to what emacs thinks is the matching bracket.
Likewise, pressing C-M-n on an opening bracket will make the cursor jump
to the corresponding closing bracket.

hide-show-mode might be useful to see how emacs is blocking the code,
but hide-show-mode might get to confused to be much help.


HTH,
Colin S. Miller


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