Continuing to compile my 3.5 year old D code, the compiler yields this error:


dmd -c -w -version=db_log -I. aepar_p_q3a.d
aepar_p_q3a.d(189): function std.c.stdio.sscanf (char*,char*,...)
                    does not match parameter types (char[],char[],int*,int*)
aepar_p_q3a.d(189): Error: cannot implicitly convert expression (line)
                    of type char[] to char*
aepar_p_q3a.d(189): Error: cannot implicitly convert expression (ttempl)
                    of type char[] to char*


aepar_p_q3a.d:
---snip---
int rip_Time_in_Seconds( char[] line )
{
    char[] ttempl = "%d:%d";    // Time Template
    int min, sec;

    int ret = sscanf( line, ttempl, &min, &sec );	// Line 189
    int uptime = min * 60 + sec;

    return uptime;
}
---snip---


I want to keep using "char[] line" from my main function, so
what would be the clean way to avoid the compiler error?

Would casting be "good"? :

    int ret = sscanf( cast(char*)line, cast(char*)ttempl, &min, &sec );	

Works, no compiler error, but am I hacking something I should not?


Are there any "new" Phobos native commands that should
rather be used than the probably outdated sscanf() (from
std.c.stdio: sscanf() int sscanf(char*, char*,...); )).

Thanks

AEon

AEon wrote:
> Continuing to compile my 3.5 year old D code, the compiler yields this error:
> 
> 
> dmd -c -w -version=db_log -I. aepar_p_q3a.d
> aepar_p_q3a.d(189): function std.c.stdio.sscanf (char*,char*,...)
>                     does not match parameter types (char[],char[],int*,int*)
> aepar_p_q3a.d(189): Error: cannot implicitly convert expression (line)
>                     of type char[] to char*
> aepar_p_q3a.d(189): Error: cannot implicitly convert expression (ttempl)
>                     of type char[] to char*
> 
> 
> aepar_p_q3a.d:
> ---snip---
> int rip_Time_in_Seconds( char[] line )
> {
>     char[] ttempl = "%d:%d";    // Time Template
>     int min, sec;
> 
>     int ret = sscanf( line, ttempl, &min, &sec );    // Line 189
>     int uptime = min * 60 + sec;
> 
>     return uptime;
> }
> ---snip---
> 
> 
> I want to keep using "char[] line" from my main function, so
> what would be the clean way to avoid the compiler error?
> 
> Would casting be "good"? :
> 
>     int ret = sscanf( cast(char*)line, cast(char*)ttempl, &min, &sec );   
> 
> Works, no compiler error, but am I hacking something I should not?

I don't know whether such casting is considered bad practice. Anyway, you should use the 'ptr' property of arrays instead, as it's cleaner.

    int ret = sscanf( line.ptr, ttempl.ptr, &min, &sec );

Check out http://www.digitalmars.com/d/1.0/arrays.html and look for "Dynamic Array Properties". You'll find it there.

> Are there any "new" Phobos native commands that should
> rather be used than the probably outdated sscanf() (from
> std.c.stdio: sscanf() int sscanf(char*, char*,...); )).

Sorry, can't help you there.

-Lars

Lars Kyllingstad wrote:

>> aepar_p_q3a.d:
>> ---snip---
>> int rip_Time_in_Seconds( char[] line )
>> {
>>     char[] ttempl = "%d:%d";    // Time Template
>>     int min, sec;
>>
>>     int ret = sscanf( line, ttempl, &min, &sec );    // Line 189
>>     int uptime = min * 60 + sec;
>>
>>     return uptime;
>> }
>> ---snip---

> I don't know whether such casting is considered bad practice. Anyway, you should use the 'ptr' property of arrays instead, as it's cleaner.
> 
>     int ret = sscanf( line.ptr, ttempl.ptr, &min, &sec );
> 
> Check out http://www.digitalmars.com/d/1.0/arrays.html and look for "Dynamic Array Properties". You'll find it there.

Ah... yes that looks a lot less like a "hack". Works fine.

On Thu, Sep 18, 2008 at 8:26 AM, AEon <aeon2001@lycos.de> wrote:
> Continuing to compile my 3.5 year old D code, the compiler yields this error:
>
>
> dmd -c -w -version=db_log -I. aepar_p_q3a.d
> aepar_p_q3a.d(189): function std.c.stdio.sscanf (char*,char*,...)
>                    does not match parameter types (char[],char[],int*,int*)
> aepar_p_q3a.d(189): Error: cannot implicitly convert expression (line)
>                    of type char[] to char*
> aepar_p_q3a.d(189): Error: cannot implicitly convert expression (ttempl)
>                    of type char[] to char*
>
>
> aepar_p_q3a.d:
> ---snip---
> int rip_Time_in_Seconds( char[] line )
> {
>    char[] ttempl = "%d:%d";    // Time Template
>    int min, sec;
>
>    int ret = sscanf( line, ttempl, &min, &sec );       // Line 189
>    int uptime = min * 60 + sec;
>
>    return uptime;
> }
> ---snip---
>
>
> I want to keep using "char[] line" from my main function, so what would be the clean way to avoid the compiler error?
>
> Would casting be "good"? :
>
>    int ret = sscanf( cast(char*)line, cast(char*)ttempl, &min, &sec );
>
> Works, no compiler error, but am I hacking something I should not?

Implicit conversion from T[] to T* was removed for exactly this kind of case -- accidentally passing a D-style string to a function that expects a C-style string.  ttempl.ptr should work since the D compiler implicitly zero-terminates string literals, but line.ptr will probably not work since line could come from anywhere and may or may not have a terminating NUL character.  The proper way to do it is to toStringz(line).

>
> Are there any "new" Phobos native commands that should
> rather be used than the probably outdated sscanf() (from
> std.c.stdio: sscanf() int sscanf(char*, char*,...); )).

import std.cstream, use din.readf().

Jarrett Billingsley wrote:
> On Thu, Sep 18, 2008 at 8:26 AM, AEon <aeon2001@lycos.de> wrote:
>> Continuing to compile my 3.5 year old D code, the compiler yields this
>> error:
>>
>>
>> dmd -c -w -version=db_log -I. aepar_p_q3a.d
>> aepar_p_q3a.d(189): function std.c.stdio.sscanf (char*,char*,...)
>>                    does not match parameter types (char[],char[],int*,int*)
>> aepar_p_q3a.d(189): Error: cannot implicitly convert expression (line)
>>                    of type char[] to char*
>> aepar_p_q3a.d(189): Error: cannot implicitly convert expression (ttempl)
>>                    of type char[] to char*
>>
>>
>> aepar_p_q3a.d:
>> ---snip---
>> int rip_Time_in_Seconds( char[] line )
>> {
>>    char[] ttempl = "%d:%d";    // Time Template
>>    int min, sec;
>>
>>    int ret = sscanf( line, ttempl, &min, &sec );       // Line 189
>>    int uptime = min * 60 + sec;
>>
>>    return uptime;
>> }
>> ---snip---
>>
>>
>> I want to keep using "char[] line" from my main function, so
>> what would be the clean way to avoid the compiler error?
>>
>> Would casting be "good"? :
>>
>>    int ret = sscanf( cast(char*)line, cast(char*)ttempl, &min, &sec );
>>
>> Works, no compiler error, but am I hacking something I should not?
> 
> Implicit conversion from T[] to T* was removed for exactly this kind
> of case -- accidentally passing a D-style string to a function that
> expects a C-style string.  ttempl.ptr should work since the D compiler
> implicitly zero-terminates string literals, but line.ptr will probably
> not work since line could come from anywhere and may or may not have a
> terminating NUL character.  The proper way to do it is to
> toStringz(line).

I had forgotten all about toStringz(). Using it now, code seems to work.

AEon