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#ifndef REQUIRE_H
#define REQUIRE_H
#include <chad/experimental/bits.h>
/* Require macros for easy uniform error handling.
* They can be used to replace repeated error handling logic
* or some messier solutions.
*
* REQUIRE() and REQUIRE_EX() assert a statement,
* on failure they invoke REQUIRE_TERMINATOR,
* on success they return the resulting value.
*
* REQUIRE_EX() takes a custom error value as its first argument,
* REQUIRE() assumes standard C truthliness.
*
* Example:
* int extreme_example(int i) {
* switch (i) {
* case 1: return 4;
* case 2: return 5;
* default: return 0;
* }
* }
*
* signed main(void) {
* FILE * f = REQUIRE(fopen("a.txt", "r"));
*
* REQUIRE(3 < 5);
*
* int i = REQUIRE(extreme_example(1));
*
* return 0;
* }
* Possible (stderr) output:
* Required operation 'fopen("a.txt", "r")' failed.
*/
thread_local long long require_v;
#ifndef REQUIRE_TERMINATOR
# define REQUIRE_TERMINATOR(...) default_require_terminator(__VA_ARGS__)
#endif
[[ noreturn ]]
static inline
void require_default_terminator(const char * const argv) {
fprintf(stderr, "Required operation '%s' failed.\n", argv);
exit(1);
}
#define REQUIRE_EX(errval, ...) (typeof(__VA_ARGS__))( \
(typeof(__VA_ARGS__))(require_v = (long long)(__VA_ARGS__)) != (typeof(__VA_ARGS__))errval \
? require_v \
: (REQUIRE_TERMINATOR(STRINGIFY(__VA_ARGS__)), 0ll) \
)
#define REQUIRE(...) REQUIRE_EX(0ll, __VA_ARGS__)
#endif
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