makefile计算差异失败
makefile computing diff fails
当我尝试计算两个文本文件之间的 diff 时：
results.txt: file1.txt file2.txt
diff $(word 1,$^) $(word 2,$^) > $@
我收到这个奇怪的 (?) 错误：
$ make
diff file1.txt file2.txt > results.txt
makefile:2: recipe for target 'results.txt' failed
make: *** [results.txt] Error 1
我的 makefile 有什么问题？
问题是如果文件不同，diff 通常有一个 non-zero 退出代码。这将导致 make 推断命令失败。简单的解决方法是告诉 make 到 ignore the exit code...
results.txt: file1.txt file2.txt
-diff $(word 1,$^) $(word 2,$^) > $@
编辑： 如果目的是完全消除诊断消息，那么您可以使用诸如...
results.txt: file1.txt file2.txt
diff $(word 1,$^) $(word 2,$^) > $@ || exit 0
当我尝试计算两个文本文件之间的 diff 时：
results.txt: file1.txt file2.txt
diff $(word 1,$^) $(word 2,$^) > $@
我收到这个奇怪的 (?) 错误：
$ make
diff file1.txt file2.txt > results.txt
makefile:2: recipe for target 'results.txt' failed
make: *** [results.txt] Error 1
我的 makefile 有什么问题？
问题是如果文件不同，diff 通常有一个 non-zero 退出代码。这将导致 make 推断命令失败。简单的解决方法是告诉 make 到 ignore the exit code...
results.txt: file1.txt file2.txt
-diff $(word 1,$^) $(word 2,$^) > $@
编辑： 如果目的是完全消除诊断消息，那么您可以使用诸如...
results.txt: file1.txt file2.txt
diff $(word 1,$^) $(word 2,$^) > $@ || exit 0