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Stderr Checking In Pipes: trypipeerr

Checks state of each function in a pipeline and exits block on error

Description

trypipeerr checks the state of each function and exits the block if any of them fail. Where trypipeerr differs from regular tryerr blocks is trypipeerr will check every process along the pipeline as well as the terminating function (which tryerr only validates against). The downside to this is that piped functions can no longer run in parallel.

Usage

trypipeerr { code-block } -> <stdout>

<stdin> -> trypipeerr { -> code-block } -> <stdout>

Examples

trypipeerr {
    out "Hello, World!" -> grep: "non-existent string" -> cat
    out "This command will be ignored"
}

Formated pager (less) where the pager isn’t called if the formatter (pretty) fails (eg input isn’t valid JSON):

func pless {
    -> trypipeerr { -> pretty -> less }
}

Detail

A failure is determined by:

• Any process that returns a non-zero exit number
• Any process that returns more output via stderr than it does via stdout

You can see which run mode your functions are executing under via the fid-list command.

See Also

• Caught Error Block: catch: Handles the exception code raised by try or trypipe
• Disable Error Handling In Block: unsafe: Execute a block of code, always returning a zero exit number
• Display Running Functions: fid-list: Lists all running functions within the current Murex session
• Function / Module Defaults: runmode: Alter the scheduler’s behaviour at higher scoping level
• If Conditional: if: Conditional statement to execute different blocks of code depending on the result of the condition
• Pipe Fail: trypipe: Checks for non-zero exits of each function in a pipeline
• Schedulers: Overview of the different schedulers (or ‘run modes’) in Murex
• Stderr Checking In TTY: tryerr: Handles errors inside a block of code
• Switch Conditional: switch: Blocks of cascading conditionals
• Try Block: try: Handles non-zero exits inside a block of code

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This document was generated from builtins/core/structs/tryerr_doc.yaml.