Commands specified to syscmd or esyscmd might need a
temporary file, for output or for some other purpose.
There is a builtin macro, maketemp, for making temporary file
names:
maketemp(template)
which expands to a name of a non-existent file, made from the string
template, which should end with the string `XXXXXX'. The six
X's are then replaced, usually with something that includes the
process id of the m4 process, in order to make the filename unique.
maketemp(`/tmp/fooXXXXXX') =>/tmp/fooa07346 maketemp(`/tmp/fooXXXXXX') =>/tmp/fooa07346
As seen in the example, several calls of maketemp might expand to
the same string, since the selection criteria is whether the file exists
or not. If a file has not been created before the next call, the two
macro calls might expand to the same name.
The builtin macro maketemp is recognized only when given
arguments.
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