Some software are built that way. A typical example is SQLite. It is sometimes compiled as an amalgamation (done at build time from many source files). But that approach has pros and cons. Obviously, the compile time will increase by quite a lot. So it is practical only if you compile that stuff rarely. Perhaps, … Read more
Macros don’t directly expand recursively, but there are workarounds. When the preprocessor scans and expands pr(5): pr(5) ^ it creates a disabling context, so that when it sees pr again: ((5==1)? 1 : pr(5-1)) ^ it becomes painted blue, and can no longer expand, no matter what we try. But we can prevent our macro … Read more
Is the second code snippet analogous to the one in C? More or less. It’s is more powerful, as you can include <<-separated values in the argument, so with a single argument you get something that would require a variable number of macro arguments in C. On the other hand, there is a slim chance … Read more
Yes, it can be relied upon. The C99 standard specifies at §6.10.1 ¶3: After all replacements due to macro expansion and the defined unary operator have been performed, all remaining identifiers are replaced with the pp-number 0 Edit Sorry, I thought it was a C question; still, no big deal, the equivalent section in the … Read more
NASA’s Goddard Space Flight Center (GSFC) rules for headers in C state that it must be possible to include a header in a source file as the only header, and that code using the facilities provided by that header will then compile. This means that the header must be self-contained, idempotent and minimal: self-contained — … Read more
#if !defined(MANUF) || !defined(SERIAL) || !defined(MODEL)
No, C# does not support preprocessor macros like C. Visual Studio on the other hand has snippets. Visual Studio’s snippets are a feature of the IDE and are expanded in the editor rather than replaced in the code on compilation by a preprocessor.
see http://www.decompile.com/cpp/faq/file_and_line_error_string.htm specifically: #define STRINGIFY(x) #x #define TOSTRING(x) STRINGIFY(x) #define AT __FILE__ “:” TOSTRING(__LINE__) so your problem can be solved by doing sscanf(buf, “%” TOSTRING(MAX_LEN) “s”, val);
The #define is part of the preprocessor language for C and C++. When they’re used in code, the compiler just replaces the #define statement with what ever you want. For example, if you’re sick of writing for (int i=0; i<=10; i++) all the time, you can do the following: #define fori10 for (int i=0; i<=10; … Read more
Macro expansion is a complex process that is really only understandable by understanding the steps that occur. When a macro with arguments is recognized (macro name token followed by ( token), the following tokens up to the matching ) are scanned and split (on , tokens). No macro expansion happens while this is happening (so … Read more