Blanket bomb a C source file with function entry/exit trace

'Blanket bomb' a file with trace for function entry / exit, from vim:

:%s/^{/{\r\ \ \ \ printf(">>>%s:%d\\n", __FUNCTION__,__LINE__);\r/
:%s/\(\ *\)\(return.*\n\)/\1printf("<<<%s:%d\\n", __FUNCTION__,__LINE__);\r\1\2/

or just using sed from the command line:

sed 's/^{/{\n\ \ \ \ printf(">>>%s:%d\\n", __FUNCTION__,__LINE__);\n/' Filename.c > Filename.c
sed 's/\(\ *\)\(return.*\n\)/\1printf("<<<%s:%d\\n", __FUNCTION__,__LINE__);\n\1\2/' Filename.c > Filename.c