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AS/400 Programming
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Using IFS APIs w/ILE RPG
Question:
Sometime back, someone posted the correct way to write data to an IFS file
using ILE RPG and the IFS write() API. I didn't bother looking at it
because I use the QDCXLATE program to translate from EBCDIC to ASCII
before writing. Now, I want to read from an IFS file (using read()) and
then write a different file back out. Most IFS files that I read work fine
but I've run into one from an outside vendor that doesn't work. The file
is in ASCII, but when I write it back out, it gets translated back to
EBCDIC. I verified this by converting the data using QDCXLATE before
writing back out. Does anyone have the correct way of doing this? It had
something to do with the codepage parameter.
Answer(s):
Here is some code for writing and reading files to the IFS system. My
understanding was you had to open the file with create first so that the
conversion with the code page will work properly. I know the following code
works good.
D RC S 10I 0
D FileNam S 50A INZ('/qualcomm/test1'
D FileNamP S * INZ(%ADDR(FileNam))
D FileDescr S 10I 0
D O_CREAT S 10I 0 INZ(8)
D O_RDWR S 10I 0 INZ(4)
D O_TEXTDATA S 10I 0 INZ(16777216)
D O_CODEPAGE S 10I 0 INZ(8388608)
D Oflag S 10I 0 INZ(0)
D Omode S 10U 0 INZ(511)
D cp S 10U 0 INZ(819)
D ZeroBin S 1A INZ(*ALLX'00')
D NLZero S 2A INZ(X'1500')
D SI_Fmt S 50A INZ('\n')
D SI_FmtP S * INZ(%ADDR(SI_Fmt))
D SI_Msg S 50A
D SI_MsgP S * INZ(%ADDR(SI_Msg))
D Num_DS DS
D Num_Hex 4A INZ(X'00000000')
D Num 10I 0 OVERLAY(Num_Hex)
D Buf S 100A
D BufP S * INZ(%ADDR(Buf))
D BufLen S 10U 0
D/copy IFSHEAD
C EVAL FileNam = %TRIM(FileNam) + ZeroBin
C Z-add O_CREAT Oflag
C Add O_RDWR Oflag
C Add O_CODEPAGE Oflag
C EVAL FileDescr=open(FileNamP:Oflag:Omode:cp)
C IF FileDescr = -1
C EVAL RC = perror(FileNamP)
C Return
C ENDIF
C EVAL RC = close(FileDescr)
C IF RC = -1
C EVAL RC = perror(FileNamP)
C Return
C ENDIF
C Z-Add O_RDWR Oflag
C Add O_TEXTDATA Oflag
C EVAL FileDescr=open(FileNamP:Oflag)
C IF FileDescr = -1
C EVAL RC = perror(FileNamP)
C Return
C ENDIF
C EVAL Buf='This is a Test number 1' + X'25'
C X'25' SCAN Buf BufLen 30
C EVAL RC = write(FileDescr: BufP: BufLen)
C IF RC = -1
C EVAL RC = perror(FileNamP)
C Return
C ENDIF
* Close the File
C EVAL RC = close(FileDescr)
C IF FileDescr = -1
C EVAL RC = perror(FileNamP)
C Return
C ENDIF
The following is the IFSHEAD file that I copy in..
There are defined routines here that I use in other programs .. I just keep
them all together as I create new headers for C functions..
Dperror PR 10I 0 EXTPROC('perror')
Dconst * VALUE
Dsprintf PR 10I 0 EXTPROC('sprintf')
D * VALUE
D * VALUE
D 10I 0 VALUE OPTIONS(*NOPASS)
D * VALUE OPTIONS(*NOPASS)
* Open Operations
* value returned = file descriptor 0 (OK), -1 (Error)
Dopen PR 10I 0 EXTPROC('open')
D * VALUE
D 10I 0 VALUE
D 10U 0 VALUE OPTIONS(*NOPASS)
D 10U 0 VALUE OPTIONS(*NOPASS)
* Read Operations
* value returned = number of bytes read or , -1 (Error)
Dread PR 10I 0 EXTPROC('read')
D 10I 0 VALUE
D * Value
D 10U 0 VALUE
* Write Operations
* value returned = number of bytes Written or , -1 (Error)
Dwrite PR 10I 0 EXTPROC('write')
D 10I 0 VALUE
D * VALUE
D 10U 0 VALUE
* Close Operations
* value returned = 0 (OK) or , -1 (Error)
Dclose PR 10I 0 EXTPROC('close')
D 10I 0 VALUE
* Open Directory Operation
* value returned = file descriptor 0 (OK), -1 (Error)
Dopendir PR * EXTPROC('opendir')
D * VALUE
* Read Directory Operation
*
Dreaddir PR * EXTPROC('readdir')
D * VALUE
* Open Directory Operation
* value returned = 0 (OK) or , -1 (Error)
Dclosedir PR 10I 0 EXTPROC('closedir')
D * VALUE
* Unlink a File from system... Delete File
* value returned = 0 (OK) or , -1 (Error)
Dunlink PR 10I 0 EXTPROC('unlink')
D * VALUE
I had to do some research to make it work.
After a few hours I found UNISTD.H in QSYSINC which tells me I have to setup
an environment variable of QIBM_USE_DESCRIPTOR_STDIO and make it's value
"Y"
to get the reserved file descriptors. I also had to dig to figure out that
I have to bind to service program QC2LE in QSYS to take advantage of SPRINTF
and PERROR.
<Ed
Davidson, via mailing list, 1/2000>
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