Using Sequential Files
ChapterA 9.A Input/Output Processing

READ format or WRITE or WRITE *

WRAP

Write the entire argument, but anytime $X is about to exceed WIDTH: insert a <LF> character, set $X to 0, increment $Y

Similar to VARIABLE but no <LF>

READ format or WRITE or WRITE *

NOWRAP

Update $X based on STREAM or VARIABLE format as described below

Same as VARIABLE

STREAM: Write all of the argument with no truncation nor with a line terminator being inserted. Add length of argument to $X.

VARIABLE ($X=WIDTH): Write up to WIDTH-$X characters. Write no more output to the device until a WRITE ! or a SET $X makes $X less than WIDTH.

READ or WRITE !

either

Write <LF>, set $X to 0, increment $Y

Write PAD bytes to bring the current record to WIDTH

WRITE #

either

Write <FF>,<LF> or <FF>, set $X and $Y to 0. See the documentation for the USE and OPEN commands to understand how the [NO]FFLF device parameter and the gtm_nofflf environment variable affects the operation of "WRITE #". If the device parameter is unused, and the environment variable is unset, the default behavior of "WRITE #" is to write <FF>,<LF>.

Write PAD bytes to bring the current record to WIDTH, then a <FF> followed by WIDTH-1 PAD bytes

CLOSE

either

After a WRITE, if $X > 0, Write <LF>

After a WRITE, if $X >0, perform an implicit "WRITE !" adding PAD bytes to create a full record. If you need to avoid trailing PAD bytes set $X to 0 before closing a FIXED format file.

READ X

either

Return characters up to $X=WIDTH, or until encountering an <LF> or EOF. If <LF> encountered, set $X to 0, increment $Y

Return WIDTH characters; no maintenance of $X and $Y, except that EOF increments $Y

READ X#len

either

Return characters up to the first of $X=WIDTH or len characters, or encountering a <LF> or EOF; if up to len characters or EOF update $X, otherwise set $X to 0 and increment $Y

Return MIN(WIDTH, len) characters; no maintenance of $X and $Y, except that EOF increments $Y

READ *X

either

Return the code for one character and increment $X, if WIDTH=$X or <LF> encountered, set $X=0, increment $Y; if EOF return -1

Return the code for one character, if EOF return -1; no maintenance of $X and $Y, except that EOF increments $Y

See Also

[NO]FIXED

O

Controls whether records have fixed length.

[Z]LENGTH=intexpr

U

Controls virtual page length.

RECORDSIZE=intexpr

O

Specifies maximum record size.

STREAM

O

Specifies the STREAM format.

VARIABLE

O

Controls whether records have variable length.

[Z]WIDTH=intexpr

U

Controls maximum width of an output line.

[Z][NO]WRAP

O/U

Controls handling of records longer than device width.