How to debug this?

Question

Hi I am calling a function which is declared as follows: typedef char HMI_CHAR; typedef UINT32 LANG_SID_T; HmLanguage1GetString(LANG_SID_T p_sid HMI_CHAR * p_str_dest_P UINT8 p_req_length UINT8 p_cur_language_U8); Now i am calling the above function as below: HMI_CHAR *static_string; UINT8 replace_char = 0; HmLanguage1GetString(0xB4C &static_string 12 replace_char); Actually i the API which i am calling will return a string in the static_string variable which is nothing but a destination pointer. What i want to know is am i passing the parameters correctly? And one more thing i want know is after getting the string which is returned by the API how can i store the same in an array one character after the other? Note: This is pure C coding. Reply needed ASAP.

Vulpes · Answer

What I said was that it's a char array already - the chars are stored one after the other in memory - and can be iterated one by one as follows: while(!static_string[i]) printf(%c static_string[i++]);

Sam Hobbs · Answer

Karthik you really should spend some time learning the language. Any good book about C will explain that if you have a char * then you can access any char using [n]. The following works for me. void HmLanguage1GetString(LANG_SID_T p_sid HMI_CHAR * p_str_dest_P UINT8 p_req_length UINT8 p_cur_language_U8) { p_str_dest_P[1] = '*'; } int _tmain(int argc _TCHAR* argv[]) { HMI_CHAR static_string[256] = initial; UINT8 replace_char = 0; puts(static_string); HmLanguage1GetString(0xB4C static_string 12 replace_char); puts(static_string); } Given the following: char s[] = Hello; The following two lines are equivalent: *(s+1) = '*'; s[1] = '*'; In any good book about C the first chapter about pointers will explain that and even most bad books about C will.

Karthik Agarwal · Answer

No Vulpes that API returns the whole string at once. Its not character by character what you said.

Vulpes · Answer

You're not in fact passing the parameters correctly because static string is already an HMI_CHAR * so you don't need to take its address. Also you need to initialize it to create a buffer big enough for the string that is going to be returned. If say 256 bytes will be big enough I'd suggest: HMI_CHAR static_string[256]; UINT8 replace_char = 0; HmLanguage1GetString(0xB4C static_string 12 replace_char); static_string is (effectively) already a char array so you can index it to get each character. So to get the first one: HMI_CHAR first = static_string[0];