C语言 预处理器检查是否未定义多个定义
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Preprocessor check if multiple defines are not defined
提问by Toby
I have a selection of #defines in a header that are user editable and so I subsequently wish to check that the defines exist in case a user deletes them altogether, e.g.
我在用户可编辑的标题中选择了#defines，因此我随后希望检查定义是否存在，以防用户完全删除它们，例如
#if defined MANUF && defined SERIAL && defined MODEL
// All defined OK so do nothing
#else
#error "User is stoopid!"
#endif
This works perfectly OK, I am wondering however if there is a better way to check if multiple defines are NOT in place... i.e. something like:
这完全可以，但我想知道是否有更好的方法来检查多个定义是否到位......即类似：
#ifn defined MANUF || defined SERIAL ||.... // note the n in #ifn
or maybe
或者可能
#if !defined MANUF || !defined SERIAL ||....
to remove the need for the empty #if section.
消除对空 #if 部分的需要。
回答by Sergey L.
#if !defined(MANUF) || !defined(SERIAL) || !defined(MODEL)
回答by netskink
FWIW, @SergeyL's answer is great, but here is a slight variant for testing. Note the change in logical or to logical and.
FWIW，@SergeyL 的回答很好，但这里有一个轻微的测试变体。注意逻辑或逻辑与的变化。
main.c has a main wrapper like this:
main.c 有一个像这样的主要包装器：
#if !defined(TEST_SPI) && !defined(TEST_SERIAL) && !defined(TEST_USB)
int main(int argc, char *argv[]) {
// the true main() routine.
}
spi.c, serial.c and usb.c have main wrappers for their respective test code like this:
spi.c、serial.c 和 usb.c 有它们各自的测试代码的主要包装器，如下所示：
#ifdef TEST_USB
int main(int argc, char *argv[]) {
// the main() routine for testing the usb code.
}
config.h Which is included by all the c files has an entry like this:
包含在所有 c 文件中的 config.h 有一个这样的条目：
// Uncomment below to test the serial
//#define TEST_SERIAL
// Uncomment below to test the spi code
//#define TEST_SPI
// Uncomment below to test the usb code
#define TEST_USB
