Makefile comments

Several students have come with questions regarding the usage and construction of makefiles. Here are Nick Cheng's answers.

• 1. When I type 'make' in the directory where I stored all the files we are given, it gives an error message 'Makefile:5: *** missing separator. Stop.' How should I solve this problem?

  Answer:

  The lines that are indented in the Makefile should be indented with a tab character, not 8 spaces. Sometimes, through a file transfer, tabs and spaces are interchanged, which will cause your problem. So, edit your Makefile and change each set of leading spaces to a single tab.

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• 2. How do we make use of the object file we are given? What I did is type 'gcc print.o'. It then gives an error message 'ld: fatal: file print.o: unknown type, unable to process using elf(3E) libraries'.

  Answer:

  To use the object files, just place those object files in the directory where you're working and type 'make'. To ensure that these object files are used, you need to make sure these files have a later date/time than their corresponding source files (.c and .h). Type 'ls -l' to find out what the date/time is. You may have to type 'touch *.o' to force the object files to have the current date/time.