If address environments are in use, it is not possible to simply
memcpy from from one process to another. The current implementation
of env_dup does precisely this and thus, it fails at once when it is
attempted between two user processes.
The solution is to use the kernel's heap as an intermediate buffer.
This is a simple, effective and common way to do a fork().
Obviously this is not needed for kernel processes.
since many c++ library implementation reference these symbols by using ::xxx but never
really use them, the declaration avoid the unused code is pulled into the final binary
Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>
Change-Id: Idd7bf9a1e09b77a6b21f900cd3ede08a1cc82d86
This commit resolves issue #620:
Remove CONFIG_CAN_PASS_STRUCTS #620
The configuration option CONFIG_CAN_PASS_STRUCTS was added many years ago to support an old version of the SDCC compiler. That compiler is currently used only with the Z80 and Z180 targets. The limitation of that old compiler was that it could not pass structures or unions as either inputs or outputs. For example:
#ifdef CONFIG_CAN_PASS_STRUCTS
struct mallinfo mallinfo(void);
#else
int mallinfo(FAR struct mallinfo *info);
#endif
And even leads to violation of a few POSIX interfaces like:
#ifdef CONFIG_CAN_PASS_STRUCTS
int sigqueue(int pid, int signo, union sigval value);
#else
int sigqueue(int pid, int signo, FAR void *sival_ptr);
#endif
This breaks the 1st INVIOLABLES rule:
Strict POSIX compliance
-----------------------
o Strict conformance to the portable standard OS interface as defined at
OpenGroup.org.
o A deeply embedded system requires some special support. Special
support must be minimized.
o The portable interface must never be compromised only for the sake of
expediency.
o Expediency or even improved performance are not justifications for
violation of the strict POSIX interface
Also, it appears that the current SDCC compilers have resolve this issue and so, perhaps, this is no longer a problem: z88dk/z88dk#1132
NOTE: This commit cannot pass the PR checks because it depends on matching changes to the apps/ directory.
Xiang Xiao