Experimental Physics and
Industrial Control System

Hi timesir –

 

This is how the build system generates the .d (dependency) files for each of the source files. See https://github.com/epics-base/epics-base/blob/7.0/configure/CONFIG_COMMON#L135 for the definition.

 

The HDEPENDS.c is the mechanism to generate these files; these are also in the same file, see https://github.com/epics-base/epics-base/blob/7.0/configure/CONFIG_COMMON#L378. For example, if HDEPENDS_METHOD = COMP then it uses the C/C++ compiler to generate these files; otherwise it uses mkmf (included in tools)

 

For certain architectures (e.g. gnu ones), these are used to compile source files, see here: https://github.com/epics-base/epics-base/blob/7.0/configure/RULES_BUILD#L117 – this will attempt to include all of these .d file and if (as above) HDEPENDS_METHOD = COMP then it will try to generate those .d files by running  $(HDEPENDS.c) (a.k.a. the actual compiler), which will generate both the dependency file and the resulting object file at the same time.

 

Cheers,

 

Simon