Re: External C function called through XS not Doing The Right Thing

I'm suspecting this isn't a Perl/XS problem, but I'm head scratching. After adding some print statements in core locations in the C code just prior to the data being sent to the LCD, I get the exact same output between the C example and the Perl example, which leads me to believe the way I'm sending data in through Perl/XS is fine:

# C

sndcmd: 40
sndcmd: 12
sndcmd: 12
sndcmd: 12
sndcmd: 1
sndcmd: 2
sndcmd: 6
sndcmd: 20
sndcmd: 1
sndcmd: 2
sndcmd: 128
sndcmd: 80
sndcmd: 31
sndcmd: 17
sndcmd: 17
sndcmd: 21
sndcmd: 31
sndcmd: 17
sndcmd: 17
sndcmd: 31
put: 2
sndcmd: 2

# Perl

sndcmd: 40
sndcmd: 12
sndcmd: 12
sndcmd: 12
sndcmd: 1
sndcmd: 2
sndcmd: 6
sndcmd: 20
sndcmd: 1
sndcmd: 2
sndcmd: 128
sndcmd: 80
sndcmd: 31
sndcmd: 17
sndcmd: 17
sndcmd: 21
sndcmd: 31
sndcmd: 17
sndcmd: 17
sndcmd: 31
put: 2
sndcmd: 2
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Re^2: External C function called through XS not Doing The Right Thing by Anonymous Monk on Mar 10, 2017 at 02:12 UTC
Hi ? Are you sure about `"V0C",` ? You really want V An unsigned long (32-bit) in "VAX" (little-endian) order.* Maybe you mean "C0" as in character mode?	[reply] [d/l]
Re^3: External C function called through XS not Doing The Right Thing by stevieb (Canon) on Mar 10, 2017 at 02:15 UTC
I am not 100% sure, I've tried a few things. I just know that with "V0C*", I get the exact same parameters from a C program as I do with the Perl script in the called function. I'll re-review the pack documentation now that I at least have a workaround.	[reply]
Re^4: External C function called through XS not Doing The Right Thing by stevieb (Canon) on Mar 10, 2017 at 02:20 UTC
After reviewing the docs, because the function accepts an `unsigned char array[8]`, I went with `pack "C[8]", ...;`, as from what I can tell, that's most appropriate. This didn't solve the initial issue, but thanks for pointing that out!	[reply] [d/l] [select]