如何在 Watcom C 中定义 NORETURN 宏

Question

是否可以做一个与Open Watcom C编译器(不是C++(一起使用的#define NORETURN(x)宏？

根据精细手册，我有这个文件test.c：

#include <stdlib.h>
#ifdef __GNUC__
#define STATIC_NORETURN(sig) static void sig __attribute__((__noreturn__))
#define EXTERN_NORETURN(sig) extern void sig __attribute__((__noreturn__))
#endif
#ifdef __WATCOMC__
#pragma aux noreturn aborts;
#define STATIC_NORETURN(sig) static void __pragma("noreturn") sig
#define EXTERN_NORETURN(sig) extern void __pragma("noreturn") sig
#endif
STATIC_NORETURN(my_static_example(void));
EXTERN_NORETURN(my_extern_example(void));
static void my_static_example(void) {
exit(0);
}
void my_extern_example(void) {
my_static_example();
}

它使用 GCC 编译时没有任何错误或警告：

$ gcc -Wall -Wextra -pedantic -std=gnu99 -c test.c

但不使用 Open Watcom 1.9：

$ wine wcc386 -q -wx test.c
test.c(14): Error! E1009: Expecting ')' but found 'noreturn'
test.c(14): Error! E1026: Invalid declarator
test.c(14): Error! E1009: Expecting ',' but found 'noreturn'
test.c(14): Error! E1026: Invalid declarator
test.c(14): Error! E1009: Expecting ',' but found ')'
test.c(14): Error! E1024: Declared symbol 'my_static_example' is not in parameter list
test.c(15): Error! E1023: Storage class of parameter must be register or unspecified
test.c(15): Error! E1009: Expecting ')' but found 'noreturn'
test.c(15): Error! E1024: Declared symbol '__pragma' is not in parameter list
test.c(15): Error! E1009: Expecting ',' but found 'noreturn'
test.c(15): Error! E1026: Invalid declarator
test.c(15): Error! E1009: Expecting ',' but found ')'
test.c(15): Error! E1024: Declared symbol 'my_extern_example' is not in parameter list
test.c(17): Error! E1023: Storage class of parameter must be register or unspecified
test.c(17): Error! E1024: Declared symbol 'my_static_example' is not in parameter list
test.c(17): Error! E1076: Missing semicolon at end of declaration
test.c(22): Warning! W131: No prototype found for function 'my_static_example'
test.c(14): Warning! W202: Symbol '__pragma' has been defined, but not referenced

仔细阅读后，我认为手册说__pragma出于某种原因只能在C++代码中使用。但我不确定我是否正确理解了这一点。C是否有任何等效项不需要在每个函数定义的站点使用#pragma？我试图避免 ifdefs，所以在一个中心位置定义一个可移植的 NORETURN 宏会很好。

Answer 1

阅读 https://open-watcom.github.io/open-watcom-v2-wikidocs/cguide.html 它是：

__declspec( noreturn )
indicates to the C/C++ compiler that function does not return.
Example:
...

与stdnoreturn.h兼容，不要想出自己的风格。做：

// possibly in some noreturn.h
// maybe even name it stdnoreturn.h
#if __STDC_VERSION__ >= 201110L
#include <stdnoreturn.h>
#elif defined(__WATCOMC__)
#define noreturn __declspec(noreturn)
#else
#error
#endif
#include <stdlib.h>
static noreturn void my_static_example(void) {
exit(0);
}
noreturn void my_extern_example(void) {
my_static_example();
}

在wcc386 -q -wx test.c上编译得很好，Version 2.0.