2009/7/8 fang zhengshu
<fangzhsh07 <at> gmail.com>
2009/7/6 fang zhengshu
<fangzhsh07 <at> gmail.com>
hi all,
when I write a function in the IDL file, there is a problem:want to write a different-length string to a array and then read parts of the array to another string like:
interface test{
int write([string]char* str, int len);
int read([out,prealloc_client, size_is(size), prealloc_server]char str[], int size);
};
I modify the idl file as the following:
int write([in,string]char *str, int len)
int read([out, prealloc_client]char *str, int len)
there no error when compile it,but
I have defined a fixed size array in the server like array[256].
In the write() function I write a different length string to the array, then I want to read parts or all of the array in the read() function, the process will be like the following:
string[len] str[size]
| ^
| |
--------->array[256] -----------|
but when I put the function above and compile it, there are some error happen. I have change the size_is() with length_is() or max_is(), but there still error when I compile it. I know if I define a fix array str[256] the code can be work, but I just want to use a unfixed length array to get the string.
could someone please give me some advice?if I describe the problem clearly, please let me know.
thank you!
I don't know whether I describe what I want to do clearly,so I put the simple code below:
read-client write-client
#define STR_TO 30 #define STR_FROM 30
... ...
char str_to[SRR_TO]; char str_from[STR_FROM];
... ...
read(str_to, STR_TO); write(str_from, STR_FROM);
... ...
server
#define SIZE 256
...
char string[SIZE];
...
int write(char *str_from, int str_from)
{
//write str_from size chars of str_from array to the string array which is in server
}
int read(char *str_to, int str_to)
{
//read str_to size chars from the string array which is in server to str_to
}
Then I define write functions as the above in a .idl file,but when I compile it,there will be the following error:
terminate called after throwing an instance of 'std::out_of_range'
what(): CBEMsgBuffer::IsEarlier
make[1]: *** [test-server.c] Aborted
make[1]: *** [test-server.c] Deleting file `test-sys.h'
make[1]: *** [test-server.c] Deleting file `test-client.h'
make[1]: *** [test-server.c] Deleting file `test-client.c'
make: *** [/home/l4/tudos/build/pkg/
fifo/idl/OBJ-x86-l4v2] Error 2
must we use the format as the dice manual below?:
int read([out, prealloc_client, size_is(len)] char **str, [out,in]int *len)
and when I modify the function as
int read([out, prealloc_client, prealloc_server, size_is(len)] char *str, [out,in]int *len)
there is no error when compile it,but there will be another error called :fpage
could you give me some advice for the read function?
thank you.
--
fang,
when I run the test in qemu, the error come out:
fifo | L4RM: [PF] read at 0x00002000, ip 01800aa1, src B.02
fifo | [B.0] l4rm/lib/src/pagefault.c:81:__unknown_pf():
fifo | unhandled page fault
the execute code of fifo binary is :
...
/home/l4/tudos/build/pkg/fifo/idl/OBJ-x86-l4v2/fifo-server.c:259
l4_msgdope_t _dice_size_dope;
l4_msgdope_t _dice_send_dope;
l4_umword_t _word[2];
} _word;
} fifo_fifo_read_msg_buffer_t;
l4_umword_t _dice_str_size = (str) ? (_dice_strlen(str)+1) : 0;
1800a8b: 85 db test %ebx,%ebx
1800a8d: 0f 84 f9 00 00 00 je 1800b8c <fifo_dispatch+0x21c>
1800a93: 80 3b 00 cmpb $0x0,(%ebx)
1800a96: 0f 84 11 01 00 00 je 1800bad <fifo_dispatch+0x23d>
1800a9c: 31 c0 xor %eax,%eax
1800a9e: 66 90 xchg %ax,%ax
1800aa0: 40 inc %eax
1800aa1: 80 3c 18 00 cmpb $0x0,(%eax,%ebx,1) 1800aa5: 75 f9 jne 1800aa0 <fifo_dispatch+0x130>
1800aa7: 8d 58 01 lea 0x1(%eax),%ebx
...
the fifo-server.c:259 code is:
inline
void
fifo_read_marshal (CORBA_Object _dice_corba_obj,
int _dice_return /* out */,
l4_msgtag_t *_dice_tag,
char* str /* out */,
fifo_msg_buffer_t *_dice_msg_buffer,
CORBA_Server_Environment *_dice_corba_env)
{
...
l4_umword_t _dice_str_size = (str) ? (_dice_strlen(str)+1) : 0; ...
so anyone can give me some advice?
thank you!
--
fang,
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