Eclipse CDT- 转到#define 语句中的下一行

Question

我在 Eclipse-CDT 中工作，我有以下 #define 语句：

#define IS_ARGUMENT_NULL(arg) if (NULL == arg) {fprintf(stderr, "%s is NULL", #arg); bool isNull = true;}

该行对我来说太长了（我需要保持每行最多 80 个字符），我想知道我怎样才能通过代码下一行来编译 ok。我尝试按回车键并获得

#define IS_ARGUMENT_NULL(arg) if (NULL == arg) {fprintf(stderr, "%s is NULL", #arg);
bool isNull = true;}

但它无法编译。第二行说 "expected identifier or ‘(’ before ‘}’ token"

Answer 1

反斜杠（\）是换行符。

#define IS_ARGUMENT_NULL(arg) \
    if (NULL == arg) { \
        fprintf(stderr, "%s is NULL", #arg); \
        bool isNull = true; \
    }

来自gcc manual：

The macro's body ends at the end of the ‘#define’ line. You may continue the definition onto multiple lines, if necessary, using backslash-newline. When the macro is expanded, however, it will all come out on one line.

Eclipse CDT- 转到#define 语句中的下一行

Eclipse CDT- go to next line in #define statement

c

eclipse

c-preprocessor