Question

I’m trying to get integer or bool from database result this way:

bool tblexist = false;
int t_exists = 0;    

tblexist = (bool)sqlite3_column_text(chkStmt, 1);
t_exists = atoi(sqlite3_column_text(chkStmt, 1));

… but no one works.
Expected value from sqlite3_column_text(chkStmt, 1) is always 0 or 1.
But I get error message:

invalid conversion from ‘const unsigned char*’ to ‘const char*’
initializing argument 1 of ‘int atoi(const char*)’
||=== Build finished: 2 errors, 0 warnings ===|

How to solve this and get integer or bool on elegant way?

Answer 1

The first line, trying to convert to bool will always return true, as a string pointer will always be “true” if it’s not NULL. If you want to use this there are a couple of ways to handle this:

// 1. Dereference pointer to get first character in string
tblexist = (*sqlite3_column_text(chkStmt, 1) != '0');

// 2. Using string comparison
tblexist = (strcmp(sqlite3_column_text(chkStmt, 1), "0") != 0);

For the second, try this instead:

t_exists = atoi((const char *) sqlite3_column_text(chkStmt, 1));

This is because sqlite3_column_text returns the type const unsigned char * but atoi wants const char *.