Stderr Checking In TTY (tryerr)

Handles errors inside a block of code

Description

tryerr forces a different execution behavior where a failed process at the end of a pipeline will cause the block to terminate regardless of any functions that might follow.

It's usage is similar to try blocks in other languages (eg Java) but a closer functional example would be set -e in Bash.

To maintain concurrency within the pipeline, tryerr will only check the last function in any given pipeline (ie series of functions joined via |, ->, or similar operators). If you need the entire pipeline checked then use trypipe.

Usage

tryerr { code-block } -> <stdout>

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

Examples

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

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 Pipes (trypipeerr): Checks state of each function in a pipeline and exits block on error
• 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.