我想用它們的名字擴展每個引數，然后是值，例如：
#define LOG_VARIABLES(FORMAT, ...) NSLog(FORMAT, ##__VA_ARGS__) //Not sure what to do with ##__VA_ARGS__ here to make it expands like as described below
LOG_VARIABLES(@"%@: %@, %@: %@, %@: %@", arg1, arg2, arg3)
會擴大到
STRING_VALUE__(arg1), arg1, STRING_VALUE__(arg2), arg2, STRING_VALUE__(arg3), arg3
所以 NSLog 列印：
arg1: <arg1_value>, arg2: <arg2_value>, arg3: <arg3_value>
uj5u.com熱心網友回復：
借助Overloading Macro on Number of Arguments的幫助，您可以這樣做。
#define LOG_VARIABLES( FORMAT, ...) NSLog( FORMAT, __VA_ARGS__ )
#define STR(X) #X
#define VAL(X) @(STR(X)), X
#define LOG1( FORMAT, A ) LOG_VARIABLES( FORMAT, VAL( A ) )
#define LOG2( FORMAT, A, B ) LOG_VARIABLES( FORMAT, VAL( A ), VAL( B ) )
#define LOG3( FORMAT, A, B, C ) LOG_VARIABLES( FORMAT, VAL( A ), VAL( B ), VAL( C ) )
#define LOG4( FORMAT, A, B, C, D ) LOG_VARIABLES( FORMAT, VAL( A ), VAL( B ), VAL( C ), VAL( D ) )
#define LOG5( FORMAT, A, B, C, D, E ) LOG_VARIABLES( FORMAT, VAL( A ), VAL( B ), VAL( C ), VAL( D ), VAL( E ) )
#define LOG6( FORMAT, A, B, C, D, E, F ) LOG_VARIABLES( FORMAT, VAL( A ), VAL( B ), VAL( C ), VAL( D ), VAL( E ), VAL( F ) )
#define GET_MACRO( FORMAT, _1, _2, _3, _4, _5, _6, NAME, ... ) NAME
#define LOG_X(FORMAT,...) GET_MACRO(_0, ##__VA_ARGS__, LOG6, LOG5, LOG4, LOG3, LOG2, LOG1 )(FORMAT,__VA_ARGS__)
int main ( int argc, const char * argv [] ) {
@autoreleasepool
{
// insert code here...
NSLog(@"Hello, World!");
NSString * a = @"aa";
NSString * b = @"bb";
NSString * c = @"cc";
NSString * d = @"dd";
NSString * e = @"ee";
NSString * f = @"ff";
LOG_X(@"%@:%@",a);
LOG_X(@"%@:%@ and %@:%@",a,b);
LOG_X(@"%@:%@ and %@:%@ and %@:%@",a,b,c);
LOG_X(@"%@:%@ and %@:%@ and %@:%@ and %@:%@",a,b,c,d);
LOG_X(@"%@:%@ and %@:%@ and %@:%@ and %@:%@ and %@:%@",a,b,c,d,e);
LOG_X(@"%@:%@ and %@:%@ and %@:%@ and %@:%@ and %@:%@ and %@:%@",a,b,c,d,e,f);
}
return 0;
}
讓我趕緊補充一下，可能有更好的方法來完成您正在嘗試做的事情，這只是一個僅適用于 6 個引數的示例，但是您明白了……而且，我從您的開始，LOG_VARIABLES但沿著它演變成的方式LOG_X。
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