Multiple definition of first defined here on gcc 10.2.1 but not gcc 8.3.0 asked 3 years, 11 months ago modified 1 year, 5 months ago viewed 36k times Normally a header files only declare symbols, not define them, but there are some creative uses of conditional code that can get around this Lib.h (please think of a more descriptive name for this file) #ifdef debug #define debug_test 1 #else #define debug_test 0 #endif and then use debug_test where i used debug If you insist on a string literal for the format string (probably a good idea anyway), you can also introduce things like __file__, __line__ and __func__ into the output, which can improve the diagnostics: Here's another version that works with boolean inputs, and also supports setting the default to true
Conditionally run a job on Whether the job should run type '0 * * * *' jobs I know that this is a long time after the original query, but this may still be useful This can be done in gcc using the stringify operator #, but it requires two additional stages to be defined first #define xstr(x) str(x) #define str(x) #x the value of a macro can then be displayed with
3.4 stringification in the gcc online. There are 0 results when i search my codebase for globals. I'm getting a lot of redefinition of x.x previously defined here Please what does this error means? I have been seeing code like this usually in the start of header files #ifndef headerfile_h #define headerfile_h and at the end of the file is #endif what is the purpose of this?
Here are some common problems when the guard is omitted from a script If you import the guardless script in another script (e.g Import my_script_without_a_name_eq_main_guard), then the latter script will trigger the former to run at import time and using the second script's command line arguments This is almost always a mistake.
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