ISO C相当于支撑-组前pressions内 [英] ISO C equivalent of braced-groups within expressions
本文介绍了ISO C相当于支撑-组前pressions内的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
我怎样才能做一个标准(ISO C99)的方式下?
How can I do the following in a compliant (ISO C99) way?
#define MALLOC(type, length, message) ({ \
type * a_##__LINE__ = (type *)malloc((length) * sizeof(type)); \
assert(message && (a_##__LINE__ != NULL)); \
a_##__LINE__; \
})
double **matrix = MALLOC(double *, height, "Failed to reserve");
注:编译使用:GCC -std = C99 -pedantic ...
NB: to compile I use: gcc -std=c99 -pedantic ...
推荐答案
您不应该把为测试的malloc()
在断言()
:它不会当你做一个发布版本中进行编译。我没有使用下面的程序断言()
。
You shouldn't put the test for malloc()
in an assert()
: it won't be compiled in when you do a release build. I haven't used assert()
in the following program.
#include <stdio.h>
#include <stdlib.h>
void *mymalloc(size_t siz, size_t length,
const char *message, const char *f, int l) {
void *x = malloc(siz * length);
if (x == NULL) {
fprintf(stderr, "a.out: %s:%d: MALLOC: "
"Assertion `\"%s\" && x != ((void *)0)' failed.\n",
f, l, message);
fprintf(stderr, "Aborted\n");
exit(EXIT_FAILURE);
}
return x;
}
#define MALLOC(type, length, message)\
mymalloc(sizeof (type), length, message, __FILE__, __LINE__);
int main(void) {
int height = 100;
double **matrix = MALLOC(double *, height, "Failed to reserve");
/* work; */
free(matrix);
return 0;
}
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