makeBinaryWrapper: Document

1 files changed, 16 insertions, 2 deletions

diff --git a/doc/stdenv/stdenv.chapter.md b/doc/stdenv/stdenv.chapter.md
index b23c50e83644..55e9ae48fb16 100644
--- a/doc/stdenv/stdenv.chapter.md
+++ b/doc/stdenv/stdenv.chapter.md
@@ -774,7 +774,7 @@ The standard environment provides a number of useful functions.
 
 ### `makeWrapper` \<executable\> \<wrapperfile\> \<args\> {#fun-makeWrapper}
 
-Constructs a wrapper for a program with various possible arguments. For example:
+A setup-hook that can be added to a derivation's inputs. It adds a `makeWrapper` bash function that constructs a wrapper for a program with various possible arguments. For example:
 
 ```bash
 # adds `FOOBAR=baz` to `$out/bin/foo`’s environment
@@ -790,6 +790,14 @@ There’s many more kinds of arguments, they are documented in `nixpkgs/pkgs/bui
 
 `wrapProgram` is a convenience function you probably want to use most of the time.
 
+### `makeBinaryWrapper` \<executable\> \<wrapperfile\> \<args\> {#fun-makeBinaryWrapper}
+
+A setup-hook very similar to `makeWrapper`, only it creates a tiny compiled wrapper executable, that can be used as a shebang interpreter. This is needed mostly on Darwin, where shebangs cannot point to scripts, [due to a limitation with the `execve`-syscall](https://stackoverflow.com/questions/67100831/macos-shebang-with-absolute-path-not-working). The arguments it accepts are <!-- TODO: make them identical? --> similar to those of `makeWrapper` and they are documented in `nixpkgs/pkgs/build-support/setup-hooks/make-binary-wrapper.sh`.
+
+Compiled wrappers generated by `makeBinaryWrapper` can be inspected with `less <path-to-wrapper>` - by scrolling past the binary data you should be able to see the C code that generated the executable and there see the environment variables that were injected into the wrapper.
+
+Similarly to `wrapProgram`, the `makeBinaryWrapper` setup-hook provides a `wrapProgramBinary` with similar command line arguments.
+
 ### `substitute` \<infile\> \<outfile\> \<subs\> {#fun-substitute}
 
 Performs string substitution on the contents of \<infile\>, writing the result to \<outfile\>. The substitutions in \<subs\> are of the following form:
@@ -865,7 +873,13 @@ someVar=$(stripHash $name)
 
 Convenience function for `makeWrapper` that automatically creates a sane wrapper file. It takes all the same arguments as `makeWrapper`, except for `--argv0`.
 
-It cannot be applied multiple times, since it will overwrite the wrapper file.
+It cannot be applied multiple times, since it will overwrite the wrapper file and you will end up with double wrapping.
+
+### `wrapProgramBinary` \<executable\> \<makeBinaryWrapperArgs\> {#fun-wrapProgramBinary}
+
+Convenience function for `makeWrapperBinary` that automatically creates a sane wrapper file. It takes all the same arguments as `makeBinaryWrapper`, except for `--argv0`.
+
+It cannot be applied multiple times, since it will overwrite the wrapper file and you will end up with double wrapping.
 
 ## Package setup hooks {#ssec-setup-hooks}