path: root/include
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authorRich Felker <>2020-08-17 20:12:53 -0400
committerRich Felker <>2020-08-17 20:12:53 -0400
commitd49cf07541bb54a5ac7aec1feec8514db33db8ea (patch)
tree2ac42a1da8400e3817f233748e7abf0ddb337988 /include
parent22359b54ab9a3ff0a854490f3eb0fcb838e785af (diff)
add gettid function
this is a prerequisite for addition of other interfaces that use kernel tids, including futex and SIGEV_THREAD_ID. there is some ambiguity as to whether the semantic return type should be int or pid_t. either way, futex API imposes a contract that the values fit in int (excluding some upper reserved bits). glibc used pid_t, so in the interest of not having gratuitous mismatch (the underlying types are the same anyway), pid_t is used here as well. while conceptually this is a syscall, the copy stored in the thread structure is always valid in all contexts where it's valid to call libc functions, so it's used to avoid the syscall.
Diffstat (limited to 'include')
1 files changed, 1 insertions, 0 deletions
diff --git a/include/unistd.h b/include/unistd.h
index 7bcbff94..07584a23 100644
--- a/include/unistd.h
+++ b/include/unistd.h
@@ -190,6 +190,7 @@ int syncfs(int);
int euidaccess(const char *, int);
int eaccess(const char *, int);
ssize_t copy_file_range(int, off_t *, int, off_t *, size_t, unsigned);
+pid_t gettid(void);
#if defined(_LARGEFILE64_SOURCE) || defined(_GNU_SOURCE)