For example, how to avoid writing the 'func_name' twice?
#ifndef TEST_FUN
# define TEST_FUN func_name
# define TEST_FUN_NAME "func_name"
#endif
I'd like to follow the Single Point of Truth rule.
Version of C preprocessor:
$ cpp --version
cpp (GCC) 4.1.2 20070626 (Red Hat 4.1.2-14)
This question is related to
c
c-preprocessor
dry
#include <stdio.h>
#define QUOTEME(x) #x
#ifndef TEST_FUN
# define TEST_FUN func_name
# define TEST_FUN_NAME QUOTEME(TEST_FUN)
#endif
int main(void)
{
puts(TEST_FUN_NAME);
return 0;
}
Reference: Wikipedia's C preprocessor page
#define TEST_FUN_NAME #FUNC_NAME
see here
@Jonathan Leffler: Thank you. Your solution works.
A complete working example:
/** compile-time dispatch
$ gcc -Wall -DTEST_FUN=another_func macro_sub.c -o macro_sub && ./macro_sub
*/
#include <stdio.h>
#define QUOTE(name) #name
#define STR(macro) QUOTE(macro)
#ifndef TEST_FUN
# define TEST_FUN some_func
#endif
#define TEST_FUN_NAME STR(TEST_FUN)
void some_func(void)
{
printf("some_func() called\n");
}
void another_func(void)
{
printf("do something else\n");
}
int main(void)
{
TEST_FUN();
printf("TEST_FUN_NAME=%s\n", TEST_FUN_NAME);
return 0;
}
Example:
$ gcc -Wall -DTEST_FUN=another_func macro_sub.c -o macro_sub && ./macro_sub
do something else
TEST_FUN_NAME=another_func
#include <stdio.h>
#define QUOTEME(x) #x
#ifndef TEST_FUN
# define TEST_FUN func_name
# define TEST_FUN_NAME QUOTEME(TEST_FUN)
#endif
int main(void)
{
puts(TEST_FUN_NAME);
return 0;
}
Reference: Wikipedia's C preprocessor page
#define TEST_FUN_NAME #FUNC_NAME
see here
#include <stdio.h>
#define QUOTEME(x) #x
#ifndef TEST_FUN
# define TEST_FUN func_name
# define TEST_FUN_NAME QUOTEME(TEST_FUN)
#endif
int main(void)
{
puts(TEST_FUN_NAME);
return 0;
}
Reference: Wikipedia's C preprocessor page
@Jonathan Leffler: Thank you. Your solution works.
A complete working example:
/** compile-time dispatch
$ gcc -Wall -DTEST_FUN=another_func macro_sub.c -o macro_sub && ./macro_sub
*/
#include <stdio.h>
#define QUOTE(name) #name
#define STR(macro) QUOTE(macro)
#ifndef TEST_FUN
# define TEST_FUN some_func
#endif
#define TEST_FUN_NAME STR(TEST_FUN)
void some_func(void)
{
printf("some_func() called\n");
}
void another_func(void)
{
printf("do something else\n");
}
int main(void)
{
TEST_FUN();
printf("TEST_FUN_NAME=%s\n", TEST_FUN_NAME);
return 0;
}
Example:
$ gcc -Wall -DTEST_FUN=another_func macro_sub.c -o macro_sub && ./macro_sub
do something else
TEST_FUN_NAME=another_func
@Jonathan Leffler: Thank you. Your solution works.
A complete working example:
/** compile-time dispatch
$ gcc -Wall -DTEST_FUN=another_func macro_sub.c -o macro_sub && ./macro_sub
*/
#include <stdio.h>
#define QUOTE(name) #name
#define STR(macro) QUOTE(macro)
#ifndef TEST_FUN
# define TEST_FUN some_func
#endif
#define TEST_FUN_NAME STR(TEST_FUN)
void some_func(void)
{
printf("some_func() called\n");
}
void another_func(void)
{
printf("do something else\n");
}
int main(void)
{
TEST_FUN();
printf("TEST_FUN_NAME=%s\n", TEST_FUN_NAME);
return 0;
}
Example:
$ gcc -Wall -DTEST_FUN=another_func macro_sub.c -o macro_sub && ./macro_sub
do something else
TEST_FUN_NAME=another_func
#define TEST_FUN_NAME #FUNC_NAME
see here
@Jonathan Leffler: Thank you. Your solution works.
A complete working example:
/** compile-time dispatch
$ gcc -Wall -DTEST_FUN=another_func macro_sub.c -o macro_sub && ./macro_sub
*/
#include <stdio.h>
#define QUOTE(name) #name
#define STR(macro) QUOTE(macro)
#ifndef TEST_FUN
# define TEST_FUN some_func
#endif
#define TEST_FUN_NAME STR(TEST_FUN)
void some_func(void)
{
printf("some_func() called\n");
}
void another_func(void)
{
printf("do something else\n");
}
int main(void)
{
TEST_FUN();
printf("TEST_FUN_NAME=%s\n", TEST_FUN_NAME);
return 0;
}
Example:
$ gcc -Wall -DTEST_FUN=another_func macro_sub.c -o macro_sub && ./macro_sub
do something else
TEST_FUN_NAME=another_func
Source: Stackoverflow.com