if size_t_is_usize is set to true, and bindgen handles a size_t, and size_t ≠ uintptr_t, bindgen should abort #1903
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dkg
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Oct 16, 2020
Fixes: rust-lang#1901 (see also: rust-lang#1903)
geofft
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…ng#1901, rust-lang#1903) This addresses the underlying issue identified in rust-lang#1671, that size_t (integer that can hold any object size) isn't guaranteed to match usize, which is defined more like uintptr_t (integer that can hold any pointer). However, on almost all platforms, this is true, and in fact Rust already uses usize extensively in contexts where size_t would be more appropriate, such as slice indexing. So, it's better for ergonomics when interfacing with C code to map the C size_t type to usize. (See also discussion in rust-lang/rust#65473 about how usize really should be defined as size_t, not uintptr_t.) The previous fix for rust-lang#1671 removed the special case for size_t and defaulted to binding it as a normal typedef. This change effectively reverts that and goes back to mapping size_t to usize (and ssize_t to isize), but also ensures that if size_t is emitted, the typedef'd type of size_t in fact is compatible with usize (defined by checking that the size and alignment match the target pointer width). For (hypothetical) platforms where this is not true, or for compatibility with the default behavior of bindgen between 0.53 and this commit, onwards, you can disable this mapping with --no-size_t-is-usize.
pvdrz
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Sep 22, 2022
…ng#1901, rust-lang#1903) This addresses the underlying issue identified in rust-lang#1671, that size_t (integer that can hold any object size) isn't guaranteed to match usize, which is defined more like uintptr_t (integer that can hold any pointer). However, on almost all platforms, this is true, and in fact Rust already uses usize extensively in contexts where size_t would be more appropriate, such as slice indexing. So, it's better for ergonomics when interfacing with C code to map the C size_t type to usize. (See also discussion in rust-lang/rust#65473 about how usize really should be defined as size_t, not uintptr_t.) The previous fix for rust-lang#1671 removed the special case for size_t and defaulted to binding it as a normal typedef. This change effectively reverts that and goes back to mapping size_t to usize (and ssize_t to isize), but also ensures that if size_t is emitted, the typedef'd type of size_t in fact is compatible with usize (defined by checking that the size and alignment match the target pointer width). For (hypothetical) platforms where this is not true, or for compatibility with the default behavior of bindgen between 0.53 and this commit, onwards, you can disable this mapping with --no-size_t-is-usize.
pvdrz
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Sep 24, 2022
…ng#1901, rust-lang#1903) This addresses the underlying issue identified in rust-lang#1671, that size_t (integer that can hold any object size) isn't guaranteed to match usize, which is defined more like uintptr_t (integer that can hold any pointer). However, on almost all platforms, this is true, and in fact Rust already uses usize extensively in contexts where size_t would be more appropriate, such as slice indexing. So, it's better for ergonomics when interfacing with C code to map the C size_t type to usize. (See also discussion in rust-lang/rust#65473 about how usize really should be defined as size_t, not uintptr_t.) The previous fix for rust-lang#1671 removed the special case for size_t and defaulted to binding it as a normal typedef. This change effectively reverts that and goes back to mapping size_t to usize (and ssize_t to isize), but also ensures that if size_t is emitted, the typedef'd type of size_t in fact is compatible with usize (defined by checking that the size and alignment match the target pointer width). For (hypothetical) platforms where this is not true, or for compatibility with the default behavior of bindgen between 0.53 and this commit, onwards, you can disable this mapping with --no-size_t-is-usize.
qsdrqs
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Oct 26, 2022
…ng#1901, rust-lang#1903) This addresses the underlying issue identified in rust-lang#1671, that size_t (integer that can hold any object size) isn't guaranteed to match usize, which is defined more like uintptr_t (integer that can hold any pointer). However, on almost all platforms, this is true, and in fact Rust already uses usize extensively in contexts where size_t would be more appropriate, such as slice indexing. So, it's better for ergonomics when interfacing with C code to map the C size_t type to usize. (See also discussion in rust-lang/rust#65473 about how usize really should be defined as size_t, not uintptr_t.) The previous fix for rust-lang#1671 removed the special case for size_t and defaulted to binding it as a normal typedef. This change effectively reverts that and goes back to mapping size_t to usize (and ssize_t to isize), but also ensures that if size_t is emitted, the typedef'd type of size_t in fact is compatible with usize (defined by checking that the size and alignment match the target pointer width). For (hypothetical) platforms where this is not true, or for compatibility with the default behavior of bindgen between 0.53 and this commit, onwards, you can disable this mapping with --no-size_t-is-usize.
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Many projects (including nettle-sys, linux-kernel-module-rust, nodejs-sys, bcc-sys) are moving to revert to the pre-0.53 behavior that maps
size_tandusize. These projects (and many others if #1902 is merged) will fail subtly if they use bindgen over a C API that includessize_ton a weird niche platform wheresize_t≠uintptr_t. ifbindgendetects that this situation is happening, it should produce an error.the three conditions that should produce an error (all conditions must be present) are:
size_t_is_usizeis set totruesize_tsize_tis not the same underlying type asuintptr_t(see also #1901 and #1671 for background)
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