14 The GNAT Metric Tool gnatmetric

The gnatmetric tool is an ASIS-based utility for computing various program metrics. It takes an Ada source file as input and generates a file containing the metrics data as output. Various switches control which metrics are computed and output.

gnatmetric generates and uses the ASIS tree for the input source and thus requires the input to be syntactically and semantically legal. If this condition is not met, gnatmetric will generate an error message; no metric information for this file will be computed and reported.

If the compilation unit contained in the input source depends semantically upon units in files located outside the current directory, you have to provide the source search path when invoking gnatmetric. If it depends semantically upon units that are contained in files with names that do not follow the GNAT file naming rules, you have to provide the configuration file describing the corresponding naming scheme; see the description of the gnatmetric switches below. Alternatively, you may use a project file and invoke gnatmetric through the gnat driver.

The gnatmetric command has the form

     $ gnatmetric [switches] {filename} [-cargs gcc_switches]

where

• switches specify the metrics to compute and define the destination for the output
• Each filename is the name (including the extension) of a source file to process. “Wildcards” are allowed, and the file name may contain path information. If no filename is supplied, then the switches list must contain at least one -files switch (see Other gnatmetric Switches). Including both a -files switch and one or more filename arguments is permitted.
• -cargs gcc_switches is a list of switches for gcc. They will be passed on to all compiler invocations made by gnatmetric to generate the ASIS trees. Here you can provide -I switches to form the source search path, and use the -gnatec switch to set the configuration file.

• Switches for gnatmetric