From: Walter Harms <wharms@bfs.de>
To: "libc-alpha@sourceware.org" <libc-alpha@sourceware.org>
Subject: questions to register_printf_specifier()
Date: Sun, 7 Mar 2021 11:18:03 +0000 [thread overview]
Message-ID: <6569e6623ba8441fac499f90ebc6d505@bfs.de> (raw)
hi list,
i was playing with register_printf_specifier(). the documentation is sparse,
so i need some help:
I have a working example for a two argument specifier.
(looks like printf("%w\n",arg1,arg2); )
register_printf_specifier('w',usr_printf,usr_arg);
the arginfo function looks like this (reduced version).
int usr_arg (const struct printf_info *info,
size_t n, int *argtypes,
int *size)
{
argtypes[n-1] = PA_STRING;
*size=2; // size of user-defined type ?
return 2; //return the number of need arguments
}
the comment in printf.h say i should fill argtypes. I figured out that n
is the pos in argtypes i have to fill. Begs the questions:
What is the use of *size ? it seems i can set it to any value without any effect.
note: i am not a list member, please always CC
re,
wh
next reply other threads:[~2021-03-07 11:18 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-07 11:18 Walter Harms [this message]
2021-03-08 8:05 ` Florian Weimer
2021-03-09 16:20 ` AW: " Walter Harms
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