我使用gcc在linux中编译了我的C程序并保存了所有临时文件。在.i文件中，stdio.h文件已经扩展。我一直试图阅读它，但我无法理解几条初始线的含义。
# 1 "<built-in>"
# 1 "<command-line>"
# 1 "app.c"
# 1 "/usr/include/stdio.h" 1 3 4
# 28 "/usr/include/stdio.h" 3 4
# 1 "/usr/include/features.h" 1 3 4
# 313 "/usr/include/features.h" 3 4
# 1 "/usr/include/bits/predefs.h" 1 3 4
# 314 "/usr/include/features.h" 2 3 4
# 346 "/usr/include/features.h" 3 4
# 1 "/usr/include/sys/cdefs.h" 1 3 4
# 353 "/usr/include/sys/cdefs.h" 3 4
# 1 "/usr/include/bits/wordsize.h" 1 3 4
# 354 "/usr/include/sys/cdefs.h" 2 3 4
# 347 "/usr/include/features.h" 2 3 4
我认为＃符号后面的数字是行号，但每行末尾1,2,3,4的重要性是什么？在此先感谢：）