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lxc
Unverified Commit 84721447 by Christian Brauner
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compiler: add __returns_twice attribute

The returns_twice attribute tells the compiler that a function may return more than one time. The compiler will ensure that all registers are dead before calling such a function and will emit a warning about the variables that may be clobbered after the second return from the function. Examples of such functions are setjmp and vfork. The longjmp-like counterpart of such function, if any, might need to be marked with the noreturn attribute. Signed-off-by: 's avatarChristian Brauner <christian.brauner@ubuntu.com>
parent 45760f62
Showing with 6 additions and 1 deletion
src/lxc/compiler.h
......@@ -59,6 +59,10 @@
# define __hot __attribute__((hot))
#endif
#ifndef __returns_twice
#define __returns_twice __attribute__((returns_twice))
#endif
#define __cgfsng_ops
#endif /* __LXC_COMPILER_H */
src/lxc/raw_syscalls.c
......@@ -9,6 +9,7 @@
#include <sys/syscall.h>
#include <unistd.h>
#include "compiler.h"
#include "config.h"
#include "macro.h"
#include "raw_syscalls.h"
......@@ -32,7 +33,7 @@ int lxc_raw_execveat(int dirfd, const char *pathname, char *const argv[],
* The nice thing about this is that we get fork() behavior. That is
* lxc_raw_clone() returns 0 in the child and the child pid in the parent.
*/
pid_t lxc_raw_clone(unsigned long flags)
__returns_twice pid_t lxc_raw_clone(unsigned long flags)
{
/*
* These flags don't interest at all so we don't jump through any hoops
......
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