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

---

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