Q: How can you tell what library contains a certain unix function? You need to know in order to include that library on the LIBS = line of your makefile (or, preferably, on the OTHER_LIBS line of your Makefile.preamble).\
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A: The information is contained in intro(3). Type:\
man 3 intro\
as a shell command. Or from Edit, Utilities submenu, choose Manual..., and provide the string "3 intro".\