Someone sent me some gnu::cleanup code with a question, and while answering it I noticed something:
the code using defer compiled to slimmer assembly in many compilers.
(gnu::cleanup first, defer second)
Björkus 'No time_t to Die' Dorkus
@__phantomderp
The C Standard Cannot Be Replaced And Will Never Be Destroyed. ➡ thephd.dev | Avatar @KIINGKIISMET | Banner @Reckless_Moss
![Example cleanup code using POSIX's open/close functions for file descirptors:
#include <fcntl.h>
#include <unistd.h>
void closep(void* ptr) {
int* p = ptr;
if (!p || *p == -1) return;
close(*p);
}
#define return_fd(desc) return ({ auto t = desc; desc = -1; t; })
int f () {
[[gnu::cleanup(closep)]]
int fd = open("", 0, 0);
if (fd < 0)
return -1; // Safe since closep checks for < 0
bool failure = false;
// ...
if (failure)
return -1;
// ...
return_fd(fd); // Again safe
}
int main () {
return 0;
}](/web/20210226063146if_/https://code.visualstudio.com/assets/github-https-pbs.twimg.com/media/HQ05lL5XUAAH4OA?format=webp&name=medium)
