Functions as a single Macro

[praveenkumarm]

I want to convert two functions into a single macro in which the sprintf() will have varying arguments and the second function will have the fixed length of arguments

for eg:

1. sprintf(buff,"The numbers are %u,%d, The text is %s", x,y,ch);
func((unsigned int *)buff,strlen(buff), z);

2. sprintf(buff,"hello");
func((unsigned int *)buff,strlen(buff), z);

[gpraghuram]

You want to substitute sprintf with a macro?
or you are looking for something else?


Raghu

[donbock]

Are you wondering how to write a macro that has a variable number of arguments? The answer varies:

C89: can't do it.
C99: Yes! It can be done.
Gnu C: Nonportable extension allows for this.
C++: <I don't know>

Does your flavor of C/C++ support inline functions? Can you use that feature rather than a macro?

[praveenkumarm]

You want to substitute sprintf with a macro?
or you are looking for something else?


Raghu

I have two functions which i shoud replace with a macro the first function is sprintf and the second function called func which uses the parameter buff from sprintf

where the sprintf has the varying number of arguments

[gpraghuram]

I have two functions which i shoud replace with a macro the first function is sprintf and the second function called func which uses the parameter buff from sprintf

where the sprintf has the varying number of arguments

void LogThis(const char *fmt, ...)
You can use #define sprintf LogThis and i think you can do it.

Raghu

[praveenkumarm]

void LogThis(const char *fmt, ...)
You can use #define sprintf LogThis and i think you can do it.

Raghu

Can u put me a single macro for the following two function and what are all the declarations i can made before it

sprintf(buff,"hello");
func((unsigned int *)buff,strlen(buff), z);

[praveenkumarm]

Can u put me a single macro for the following two function and what are all the declarations i can made before it

sprintf(buff,"hello");
func((unsigned int *)buff,strlen(buff), z);

Hi Raghuram

ok i think i am not getting your answer

give me a macro to convert the following part

#ifdef LABEL

sprintf(buffer,"--------------------",................);
function((int *)buffer,strlen(buffer),variable);

#endif

----------------- indicates a string containing varying data types like %u, %d etc
................. indicates the variable for whose values the string should take

[Banfa]

C89: can't do it.

Not entirely true, there is a hack that goes like this

#define PRINT(x) printf x
 
 
PRINT(("This is a %s", "Hack"));
PRINT(("The answer is %d, in hex %x", 42, 42));
 

Note the double set of parenthesis, this causes all the parameters inside to be treated as the single parameter x. The parenthesis become part of the parameter x which can be verified by using the alternative definition of

#define PRINT(x) printf( #x "\n" )


I am not sure that is useful in this situation and I would tend to try an avoid using it anyway but the hack exists.

[donbock]

Not entirely true, there is a hack that goes like this

#define PRINT(x) printf x
 
 
PRINT(("This is a %s", "Hack"));
PRINT(("The answer is %d, in hex %x", 42, 42));
 

Note the double set of parenthesis, this causes all the parameters inside to be treated as the single parameter x. The parenthesis become part of the parameter x which can be verified by using the alternative definition of

#define PRINT(x) printf( #x "\n" )


I am not sure that is useful in this situation and I would tend to try an avoid using it anyway but the hack exists.

The doubled parentheses work for calling one function, but not so well for a macro that wants to expand into two function calls with each function getting different parameters