SystemC _ what is mean symbol "\" ??

[DS1701]

#define STREAM_REPORT_INFO(MSGID,message_stream) \
do {\
  std::ostringstream mout;\
  mout << sc_core::sc_time_stamp() << ": " << message_stream;\
  SC_REPORT_INFO(MSGID,mout.str().c_str());\
} while (0)

Hi All, I dont understand symbol "\" in above code , when I erase symbol "\" then it not working . . why we need "\" in above code , thanks

[AmeyaVS]

Hello @Hook,

The \ character is an escape sequence in C/C++.

Here is a reference https://en.m.wikipedia.org/wiki/Escape_sequences_in_C

I would recommend that you brush up your skills on C++ before continuing further.

I would recommend the book "The C++ Programming Language
Book by Bjarne Stroustrup".

 

Hope it helps.

Regards,

Ameya Vikram Singh

[DS1701]

thank @AmeyaVS , sorry for my question , but can you explain clear when I erase "\" above code, it not working

[Eyck]

Well, the '\' escapes the newlines at the end of each line so that the compiler treats all lines as a single line. '#define' is a pre-processor command which expects everything to be on a single line. If you do not escape the newlines then your code is one several lines and does not work anymore.

HTH

-Eyck

[David Black]

To be slightly more precise, the back-slash character (\) has two contexts. In this context, it is an escape character for CPP, the C Pre-Processor. It should only be used when using the pre-processor #define directive. Without \, the #define must be kept entirely on a single line.

The other context for which \ is used, is inside literal strings and and character constants. Examples: "Hello world\r\n" and "\n". In these cases, it serves to provide an escape to introduce non-printable ASCII characters.

 

[DS1701]

thanks all ,