C pre-processor defining for generated function names
22,557
You need to provide an extra level of "function-like macro" to ensure the proper expansion:
e.g.
#define SIGNAL1 SignalName1
#define SIGNAL2 SignalName2
#define MAKE_FN_NAME(x) void Callback_ ## x (void)
#define FUNCTION_NAME(signal) MAKE_FN_NAME(signal)
FUNCTION_NAME(SIGNAL1)
{
return;
}
output:
$ gcc -E prepro.cc
# 1 "prepro.cc"
# 1 "<built-in>"
# 1 "<command-line>"
# 1 "prepro.cc"
void Callback_SignalName1 (void)
{
return;
}
Author by
erik
Updated on July 09, 2022Comments
-
erik almost 2 years
I have a situation where I have quite a few generated functions, and would like to point them at some generic functions that I have created (to allow me to reuse the base code when the generated function names change).
Essentially, I have a list of function names as follows:
void Callback_SignalName1(void); void Callback_SignalName2(void); ...etc
Once these are generated, I would like to define a macro to allow them to be called generically. My idea was this, but I haven't had any luck implementing it...as the C pre-processor takes the name of the macro instead of what the macro is defined as:
#define SIGNAL1 SignalName1 #define SIGNAL2 SignalName2 #define FUNCTION_NAME(signal) (void Callback_ ## signal ## (void)) ... ... FUNCTION_NAME(SIGNAL1) { .. return; }
The issue is that I receive
void Callback_SIGNAL1(void)
instead of
void Callback_SignalName1(void)
Is there a good way around this?