2009/7/6 fang zhengshu fangzhsh07@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 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.