[Rpm-maint] rpm tag query and headerSprintf

Vento Neicapelli lascoscazzato at hotmail.com
Fri Dec 14 19:17:49 UTC 2007


Thank you very much Michael, it works!
Someone advise me not to open the rpmdb directly, he said:

<>

Do you know how to get the db instance?....

Thanks,

Vento



> Date: Fri, 14 Dec 2007 20:05:15 +0100
> From: mls at suse.de
> To: lascoscazzato at hotmail.com
> CC: rpm-maint at lists.dulug.duke.edu
> Subject: Re: [Rpm-maint] rpm tag query and headerSprintf
>
> On Fri, Dec 14, 2007 at 06:37:18PM +0000, Vento Neicapelli wrote:
>> I'm trying to use the librpm in a custom application, I use rpm 4.4.2.1 and I need your help about tag querying...
>>
>> 1) Have you got any snip of code to use the headerSprintf probably I'm doing it wrong...
>> 2) given the prototype:
>> char * headerSprintf(Header h, const char * fmt, const struct headerTagTableEntry_s * tags, const struct headerSprintfExtension_s * extensions, /*@null@*/ /*@out@*/ errmsg_t * errmsg)
>> if I understand the tag fmt should have the same format of the rpm tool (cli version) with --queryformat switch....or not?
>>
>> Below you find the code I wrote just to get familiar with rpmlib functions: it tries to search a package (by name) and then prints some tags....
> [...]
>> const char * qfmt = "[%{*:xml}\n]";
>> struct headerTagTableEntry_s hTTE;
>> struct headerSprintfExtension_s hSE;
>> sResult = headerSprintf(h, qfmt, &hTTE, &hSE, &errMsg);
>
> You shouldn't use your own extension table here, just use the ones
> from librpm:
>
> sResult = headerSprintf(h, qfmt, rpmTagTable, rpmHeaderFormats, &errMsg);
>
>> printf("ALLTAGS:\n %s",sResult);
>> free(sResult); sResult=NULL; errMsg=NULL;
>>
>> const char *qSummary="%{NAME}";
>> sResult = headerSprintf(h, qSummary, &hTTE, &hSE, &errMsg);
>
> see above
>
>>
>> if(!errMsg){
>> if(sResult){
>> printf("NAME:\n %s",sResult);
>> free(sResult); sResult=NULL; errMsg=NULL;
>> }
>> }else printf("ERROR: %s\n",errMsg);
>>
>> const char *qFiles="[%{DIRNAMES}%{BASENAMES}\n]";
>>
>> sResult = headerSprintf(h, qFiles, &hTTE, &hSE, &errMsg);
>
> This can't work as DIRNAMES and BASENAMES have different sizes. Use the
> pseudo-tag FILENAMES instead:
>
> const char *qFiles="[%{FILENAMES}\n]";
> sResult = headerSprintf(h, qFiles, rpmTagTable, rpmHeaderFormats, &errMsg);
>
> Cheers,
> Michael.
>
> --
> Michael Schroeder mls at suse.de
> SUSE LINUX Products GmbH, GF Markus Rex, HRB 16746 AG Nuernberg
> main(_){while(_=~getchar())putchar(~_-1/(~(_|32)/13*2-11)*13);}

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