Re: Language Reference, updated

[Robb Romans <robb at linux dot vnet dot ibm dot com>]

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>>>>> "MH" == Martin Hunt <hunt@redhat.com> writes:

    MH> You wrote that "valid types are limited to string ("%s") and
    MH> integer ("%d")"

    MH> That makes it sound like you can only use "%s" and "%d" in
    MH> printf.  You can also use the standard flags and conversion
    MH> specifiers from C printf.

Gotcha. Fixed.

    >> Is there a difference in SystemTap's handling of printing binary
    >> streams versus C standard syntax? Thanks.

    MH> Yes, C printf does not do binary output. Systemtap's printf does
    MH> the following:

    MH> %1n, %2n, %4n, %n - These functions instruct printf to write a
    MH> binary length at this location that is the total length of the
    MH> string written by the printf.  The field width is the number of
    MH> bytes to write. The default is "2".

    MH> %1b, %2b, %4b, %8b, %b - binary write. The field width specifies
    MH> the number of bytes to write. Default is 4 (32-bits).

    MH> Examples:

    MH> stap -e 'probe begin{for(i=97;i<123;i++) printf("%3d:
    MH> %1b%1b%1b\n",i,i,i-32,i-64); exit()}'

    MH>> stap -e 'probe begin{printf("%1n%b%b", 0xc0dedbad,
    MH>> 0x12345678);exit()}' | hexdump -C
    MH> 00000000 08 ad db de c0 78 56 34 12 |.....xV4.|

    MH>> stap -e 'probe begin{printf("%1b%1b%1blo %1b%1brld\n",
    MH>> 72,101,108,87,111);exit()}'
    MH> Hello World

Thank you for taking the time to make it clear to me. I've put your
reply into the Language Reference mostly verbatim.

Here's a fresh copy for review. I'll be on vacation after today, until
January 2nd, so look for updates and content development next year.

Attachment: SystemTap-Language-Ref-2006-12-06.tex.gz
Description: SystemTap-Language-Ref-2006-12-06.tex.gz

Attachment: SystemTap-Language-Ref-2006-12-06.ps.gz
Description: SystemTap-Language-Ref-2006-12-06.ps.gz

Regards,
Robb

- -- 
Robb Romans                     (512) 838-0419
Linux Commando                  T/L   678-0419
robb@linux.vnet.ibm.com         ARS NA5TT
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