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The __FILE__ and __LINE__ macros are built into the C Pre-Processor, and are often used for printing debug output with file names and line numbers. I need something similar, but with just the name of the directory at the end of the path. For instance if my code is in:
/home/davidc/some/path/to/some/code/foo/bar I need a macro that will just give me "bar", if the code is in /home/davidc/some/path/to/some/code/foo/bee then I need it to give me "bee".
Any thoughts? (btw, this is for a C++ application).
Update: to be clear, I'm after a macro that will give me a string containing the directory name at compile-time, I don't want to do any string-processing at runtime.
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__FILE__ is a preprocessor macro that expands to full path to the current file. __FILE__ is useful when generating log statements, error messages intended for programmers, when throwing exceptions, or when writing debugging code.
The naïve way to write the macro is like this: #define MACRO(X,Y) \ cout << "1st arg is:" << (X) << endl; \ cout << "2nd arg is:" << (Y) << endl; \ cout << "Sum is:" << ((X)+(Y)) << endl; This is a very bad solution which fails all three examples, and I shouldn't need to explain why.
The __file__ variable: __file__ is a variable that contains the path to the module that is currently being imported.
A macro is a piece of code in a program that is replaced by the value of the macro. Macro is defined by #define directive. Whenever a macro name is encountered by the compiler, it replaces the name with the definition of the macro. Macro definitions need not be terminated by a semi-colon(;).
If you are using GNU make to build your project, then you might be able to do something like this:
%.o: %.cpp
$(CC) $(CFLAGS) -D__DIR__="$(strip $(lastword $(subst /, , $(dir $(abspath $<)))))" -c $< -o $@
That has to be about the most God-awful thing that I have thought about doing in a Makefile in quite a while. I don't think that you will find a quick or clean way to do this within the confines of the compiler so I'd look for clever ways to inject the information into the compilation process.
Good luck.
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