If the same inference rule is defined in more than one place, NMAKE uses the rule with the highest precedence. The precedence from highest to lowest is as follows:
1.An inference rule defined in the makefile. If more than one rule is defined, the last rule applies.
2.An inference rule defined in the TOOLS.INI file. If more than one rule is defined, the last rule applies.
3.A predefined inference rule.
User-defined inference rules always override predefined inference rules. NMAKE uses a predefined inference rule only if no user-defined inference rule exists for a given target and dependent.
If two inference rules match a target's extension and a dependent is not specified, NMAKE uses the inference rule whose dependent's extension appears first in the .SUFFIXES list.