error: invalid conversion from ‘const char*’ to ‘char*’ [-fpermissive]

Question

I get the following error:

2 smartcard.c: In member function ‘virtual bool cSmartCards::ParseLine(const char*, bool)’:
3 smartcard.c:1187:25: error: invalid conversion from ‘const char*’ to ‘char*’ [-fpermissive]
4    char *r=index(line,':');
5                          ^

The code is:

1184
1185 bool cSmartCards::ParseLine(const char *line, bool fromCache)
1186 {
1187   char *r=index(line,':');
1188   if(!r) return false;

I included "string.h"

How can I rewrite line 1187?

index() can be found in string.h.

Answer 1

Either or both of the following:

• index returns const char*, not a char*. So, make r a const char*, not a char*.

• The function index is written to expect a char*, not a const char*. I cannot safely suggest a fix for this without knowing what index is and does.

Answer 2

答案如下：

 Function index is found in string.h.
 Change line 1187 to: const char *r=index(line,':');