Using c++ style comments in mex files.

I'm testing simple mex functions today and I would like to add some comments. However, I noticed:

1. If my comments are surrounded by "/* \*/", namely, /*comments*/, the compilation of mex file works fine.
2. But if my comments are commented in the way using "//", namely, //comments, the compilation fails.

Can anybody help to explain why it is so? Does that mean, I'm not able to write comments in the way of "//comments" in Matlab mex files?

Answer 1

[Jan]

While the LCC compiler shipped with Matlab, modern LCC versions, Borland BCC, OpenWatcom, MSVC und Intel compilers understand the C99 comment style, the GCC compiler needs to enable them explicitely on Linux:

mex('CFLAGS="\$CFLAGS -std=c99"', 'File.c')

Answer 2

[Walter Roberson]

Were you using C or C++ ? C++ has always accepted // comments, but the original 1989 C standard did not accept them. If you are using the default LCC compiler then possibly it does not accept them. You may have to specifically configure your compiler to use the C99 standard if you are using C.

[Ashish Uthama]

Confirming: LCC does not accept C++ comments.

[Jan]

I disagree. At least on LCC shipped with Matlab 5.3, 6.1, 6.5, and 2009a (LCC2.4) and the version 3.8 from the net do accpet C++ comments. I've tested all Mex functions with LCC before I posted them in the FEX - and I ever use the C99 comment style // .

[James Tursa]

Which is why I have switched to using the /* */ style in my FEX submissions, even though I prefer the // style.

[Jan]

@James: As far as I know, only GCC without -std=c99 fails to interprete this 12 year old standard. And I do not understand, why MathWorks does not include this flag as standard in the mexopts file.

Do you know other compiler, which insiste on c89 style?

[James Tursa]

No. I haven't researched this. I just got tired of all the problems that gcc users had with compiling my FEX submissions. Actually, I still write with the // style, I just use a simple conversion program after the fact to produce the files I submit.