read from process
Type
command
Summary
Accepts the output of a process that was opened with the open process command, placing the data in the it variable.
Syntax
read from process <processName> [at <start>] {until {<string> | empty | end | EOF} | for <amount> [<chunkType>]} [in <time>]
Description
Use the read from process command to get the output data from another program.
The until form reads data until the specified string is encountered. The until end and until eof forms read data until the process specifies it is finished. When until empty is used the data is read in at specified time intervals. If, when checked, the data is empty, the openProcesses function is used to check whether the process has finished.
Parameters
| Name | Type | Description |
|---|---|---|
processName | string | The processName specifies the name and location of the process you want to read from. It must be the same as the path you used with the open process command.
|
start | string | The start specifies the character or byte position in the process output where you want to begin reading. |
chunkType | The chunkType is one of chars, characters, words, items, lines, int1, uInt1, int2, uint2, int4, or uint4. The read from process command reads amount of the specified chunkType. If you don't specify a chunkType, amount characters are read. | |
time | The time is the time to wait for the read to be completed, in milliseconds, seconds, or ticks. | |
string | string | The string is any expression that evaluates to a string. When LiveCode encounters the string in the process output, it stops reading. If the string is not encountered, the read from process command continues reading as long as there is data to be read. |
amount | integer | The amount is a positive integer and specifies how much data to read. |
Examples
read from process "compileData" for 20
read from process "/etc/pr" at 2 until linefeed -- skip 2 chars
read from process myProcess for 10 int4s in 250 milliseconds
Related
control structure: function
function: openProcesses, ticks, result, milliseconds
glossary: platform, binary file, variable, byte, case-sensitive, expression, evaluate, command, process
keyword: uInt2, string, int1, characters, int4, integer, int2, real4, uInt4, stdin, it, uInt1, character, real8
command: open process, close process, write to process, read from driver
constant: EOF
Compatibility and Support
Introduced
LiveCode 1.0
OS
mac
windows
linux
Platforms
desktop
server