c - 此行有多个标记 - 语法错误（日食）

Question

我为 i2c 创建了一个头文件，来自 Peter Fleury。我在 Eclipse 中重写并在下面的列表程序的第二行中收到错误警告“此行有多个标记 - 语法错误 - 预期标识符或 '(' 在 'unsigned' 之前”

>#define    i2c_read(ack)   (ack) ? i2c_readAck() : i2c_readNak();
>
>unsigned char  i2c_read (unsigned char ack);

有人可以帮助我吗？

Answer 1

What are you trying to achieve? If you preprocess the #define macro you'll get:

unsigned char (unsigned char ack) ? i2c_readAck() : i2c_readNak();;

This isn't a legal C. I'm not familiar with i2c, and I don't know what you are trying to do. If you are trying to declare a new variable and initialize it with a value (and call the correct method), you should:

#define  i2c_read(ack)   (ack) ? i2c_readAck() : i2c_readNak()
unsigned char new_var = i2c_read (ack);

Note that I'm assuming ack is defined somewhere else. If you are trying to achieve something else, please specify it in your question. Also note I removed one semicolon from the '#define'. It is a common mistake, which typically only generate a warning or go unnoticed.

Oh, and if you are trying the declare a function, then it should have a different name than the macro.

Answer 2

You have defined a macro and declared a function with same name.
Perhaps you should change the macro name or function name.