Strange behavior

hello guys!

i have piece of code below

code: [select]


void core::sendat( const __flashstringhelper *_command, const __flashstringhelper *_response )
{
    bool completed = true;
   
    start:
    char *command  = static_cast<char*>( malloc( sizeof *command * sizeof _command ) );
    char *response = static_cast<char*>( malloc( sizeof *response * sizeof _response ) );

    byte cursor = 0;
    while ( ( command[cursor] = pgm_read_byte_near( ( char* ) _command + cursor ) ) != nul )
        cursor++;
   
    cursor = 0;   
    while ( ( response[cursor] = pgm_read_byte_near( ( char* ) _response + cursor ) ) != nul )
        cursor++;

    debug << f( "command: " ) << command << crlf;
    debug << f( "response: " ) << response << crlf;
   
    free( command );
    free( response );
}



i'm passing f() macro strings both parameters ( f( "at+restore" ), f( "ready" ) ).
both parameters giving sizeof 2.

what not expecting when code goes through first while , put debug command before second while, program prints whole string.

when located code above, getting garbage on first print , correct value second parameter.

if set malloc size manually, it's good. both values printed correctly.

why getting behavior?

thanks in advance!

sizeof _command gives size of pointer memory, 2 bytes
sizeof *command size of char, 1 byte

and 2 * 1 = 2, feels logic

strlen(_command) want (and need 1 char \0 in malloc if want proper c strings , able print them out)

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