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I am learning some other's code -- build files. Here are two samples which I am confused.
gcc -E -o ListDef -dM -P YourSrcCode.c
gcc -E -o ListDef -dD -P YourSrcCode.c
I have tried that in ListDef file (new generated after either of the two commands) and it contains several hundred lines of #define, typedef and some other definitions. Could anyone help to answer what is the function of the two commands? Differences between -dM and -dD?
I have read the gcc PDF manual and also tried by myself. I can not fully understand in what situation do we need -dM and in what situation do we need -dD. Any experiences?
dD - Dump all macro definitions, at the end of preprocessing, in addition to normal output.
dM - Dump after performing the machine dependent reorganization pass, to file.35.mach.
dD - Dump all macro definitions, at the end of preprocessing, in addition to normal output.
dM - Dump after performing the machine dependent reorganization pass, to file.35.mach.
So, using -dM is more accurate to real preprocessor work? (since you mentioned it also performed machine dependent reorganization pass)?
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