将__LINE__包装为单引号

Question

如何在M4中包含LINE和FILE宏以显示＆＃39; 4＆＃39;或＆＃34; 4＆＃34;。我希望它能够输出到控制台。我正在使用C ++。

Answer 1

Not 100% percent sure if this is what you're after but this makes __file__ to output filename in quotes (on my mac os):

define(`_m4__file__',defn(`__file__'))
pushdef(`__file__',`"_m4__file__"')

define(`_m4__line__',defn(`__line__'))
pushdef(`__line__',`"_m4__line__"')

define(`echo',`$*')
echo(__file__,__line__)
echo(__file__,__line__)

output:

"m4.t","8"
"m4.t","9"

for single quotes use a bit more escaping:

define(`_m4__file__',defn(`__file__'))
pushdef(`__file__',`''`_m4__file__'`'')

define(`_m4__line__',defn(`__line__'))
pushdef(`__line__',`''`_m4__line__'`'')

define(`echo',`$*')
echo(__file__,__line__)
echo(__file__,__line__)

outputs:

'm4.t','8'
'm4.t','9'