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| author | nicole mazzuca <83086508+strega-nil-ms@users.noreply.github.com> | 2021-07-14 14:45:18 -0500 |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2021-07-14 12:45:18 -0700 |
| commit | d369df7ecf194005eaca46f07368779cd486badd (patch) | |
| tree | 419f9861b796a7dc6e53646df13642c6c71108f2 /docs/maintainers/internal | |
| parent | 932df5b8ede16b73fc5508445140d5b360ea0c68 (diff) | |
| download | vcpkg-d369df7ecf194005eaca46f07368779cd486badd.tar.gz vcpkg-d369df7ecf194005eaca46f07368779cd486badd.zip | |
[rollup:2021-07-06] Rollup PR (#18838)
* [rollup:2021-07-06 1/8] PR #18272 (@strega-nil)
[scripts-audit] vcpkg_from_*
* [rollup:2021-07-06 2/8] PR #18319 (@strega-nil)
[scripts-audit] add guidelines for cmake
* [rollup 2021-07-06 3/8] PR #18410 (@mheyman)
[vcpkg-cmake-config] documentation fix
* [rollup:2021-07-06 4/8] PR #18488 (@strega-nil)
[scripts-audit] vcpkg_execute_*
* [rollup:2021-07-06 5/8] PR #18517 (@strega-nil)
[scripts-audit] vcpkg_extract_source_archive
* [rollup:2021-07-06 6/8] PR #18674 (@NancyLi1013)
[vcpkg doc] Update examples
* [rollup:2021-07-06 7/8] PR #18695 (@JackBoosY)
[vcpkg] Update the minimum version of vcpkg
* [rollup:2021-07-06 8/8] PR #18758 (@ras0219-msft)
[vcpkg_from_git] Fix error if downloads folder does not exist
* build docs!
* fix bond:*-windows
* fix nmap
Co-authored-by: nicole mazzuca <mazzucan@outlook.com>
Co-authored-by: Michael Heyman <Michael.Heyman@jhuapl.edu>
Co-authored-by: NancyLi1013 <lirui09@beyondsoft.com>
Co-authored-by: JackBoosY <yuzaiyang@beyondsoft.com>
Co-authored-by: Robert Schumacher <ras0219@outlook.com>
Diffstat (limited to 'docs/maintainers/internal')
| -rw-r--r-- | docs/maintainers/internal/z_vcpkg_forward_output_variable.md | 38 |
1 files changed, 38 insertions, 0 deletions
diff --git a/docs/maintainers/internal/z_vcpkg_forward_output_variable.md b/docs/maintainers/internal/z_vcpkg_forward_output_variable.md new file mode 100644 index 000000000..10c5855df --- /dev/null +++ b/docs/maintainers/internal/z_vcpkg_forward_output_variable.md @@ -0,0 +1,38 @@ +# z_vcpkg_forward_output_variable + +The latest version of this document lives in the [vcpkg repo](https://github.com/Microsoft/vcpkg/blob/master/docs/). + +This macro helps with forwarding values from inner function calls, +through a local function scope, into pointer out parameters. + +```cmake +z_vcpkg_forward_output_variable(ptr_to_parent_var var_to_forward) +``` + +is equivalent to + +```cmake +if(DEFINED ptr_to_parent_var) + if(DEFINED value_var) + set("${ptr_to_parent_var}" "${value_var}" PARENT_SCOPE) + else() + unset("${ptr_to_parent_var}" PARENT_SCOPE) + endif() +endif() +``` + +Take note that the first argument should be a local variable that has a value of the parent variable name. +Most commonly, this local is the result of a pointer-out parameter to a function. +If the variable in the first parameter is not defined, this function does nothing, +simplifying functions with optional out parameters. +Most commonly, this should be used in cases like: + +```cmake +function(my_function out_var) + file(SHA512 "somefile.txt" local_var) + z_vcpkg_forward_output_variable(out_var local_var) +endfunction() +``` + +## Source +[scripts/cmake/z\_vcpkg\_forward\_output\_variable.cmake](https://github.com/Microsoft/vcpkg/blob/master/scripts/cmake/z_vcpkg_forward_output_variable.cmake) |