用于模板的 c 预处理器 - 抑制额外的人工制品

Question

命令：

% cat <<EOF | cpp -DVERBOSE=3
#if VERBOSE >= 2
  printf("trace message");
#endif
EOF

输出：

# 1 "<stdin>"
# 1 "<built-in>" 1
# 1 "<built-in>" 3
# 362 "<built-in>" 3
# 1 "<command line>" 1
# 1 "<built-in>" 2
# 1 "<stdin>" 2

  printf("trace message");

任何人都知道如何抑制这些行，例如 # 1 "<stding>" 2，我需要在输入 Dockerfile 中包含一些指令，例如 # dockerfile syntax=experiemental。

Answer 1

how to suppress those lines such as # 1 "" 2

来自gcc manual：

-P

Inhibit generation of linemarkers in the output from the preprocessor. This might be useful when running the preprocessor on something that is not C code, and will be sent to a program which might be confused by the linemarkers.

cpp -P ...

用于模板的 c 预处理器 - 抑制额外的人工制品

c preprocessor for templating - suppress extra artefacts

c

preprocessor

dockerfile