diff --git a/src/header/limits/mod.rs b/src/header/limits/mod.rs
index 72c1170e36..cde6c86caf 100644
--- a/src/header/limits/mod.rs
+++ b/src/header/limits/mod.rs
@@ -1,4 +1,5 @@
 //! limits.h implementation for relibc
+//! Following https://pubs.opengroup.org/onlinepubs/7908799/xsh/limits.h.html
 
 pub const HOST_NAME_MAX: usize = 64;
 pub const NAME_MAX: usize = 255;
@@ -10,3 +11,46 @@ pub const NGROUPS_MAX: usize = 65536;
 // way to determine it for other archs or to hard code a value.
 #[cfg(target_os = "linux")]
 pub const PAGE_SIZE: usize = 4096;
+
+// These POSIX symbols must have these values regardless of OS
+pub const _POSIX_AIO_LISTIO_MAX: usize = 2;
+pub const _POSIX_AIO_MAX: usize = 1;
+pub const _POSIX_ARG_MAX: usize = 4096;
+pub const _POSIX_CHILD_MAX: usize = 25;
+pub const _POSIX_CLOCKRES_MIN: usize = 20000000;
+pub const _POSIX_DELAYTIMER_MAX: usize = 32;
+pub const _POSIX_HOST_NAME_MAX: usize = 255;
+pub const _POSIX_LINK_MAX: usize = 8;
+pub const _POSIX_LOGIN_NAME_MAX: usize = 9;
+pub const _POSIX_MAX_CANON: usize = 255;
+pub const _POSIX_MAX_INPUT: usize = 255;
+pub const _POSIX_NAME_MAX: usize = 14;
+pub const _POSIX_NGROUPS_MAX: usize = 8;
+pub const _POSIX_OPEN_MAX: usize = 20;
+pub const _POSIX_PATH_MAX: usize = 256;
+pub const _POSIX_PIPE_BUF: usize = 512;
+pub const _POSIX_RE_DUP_MAX: usize = 255;
+pub const _POSIX_RTSIG_MAX: usize = 8;
+pub const _POSIX_SEM_NSEMS_MAX: usize = 256;
+pub const _POSIX_SEM_VALUE_MAX: usize = 32767;
+pub const _POSIX_SIGQUEUE_MAX: usize = 32;
+pub const _POSIX_SSIZE_MAX: usize = 32767;
+pub const _POSIX_STREAM_MAX: usize = 8;
+pub const _POSIX_SYMLINK_MAX: usize = 255;
+pub const _POSIX_SYMLOOP_MAX: usize = 8;
+pub const _POSIX_THREAD_DESTRUCTOR_ITERATIONS: usize = 4;
+pub const _POSIX_THREAD_KEYS_MAX: usize = 128;
+pub const _POSIX_THREAD_THREADS_MAX: usize = 64;
+pub const _POSIX_TIMER_MAX: usize = 32;
+pub const _POSIX_TTY_NAME_MAX: usize = 9;
+pub const _POSIX_TZNAME_MAX: usize = 6;
+
+pub const _POSIX2_BC_BASE_MAX: usize = 99;
+pub const _POSIX2_BC_DIM_MAX: usize = 2048;
+pub const _POSIX2_BC_SCALE_MAX: usize = 99;
+pub const _POSIX2_BC_STRING_MAX: usize = 1000;
+pub const _POSIX2_CHARCLASS_NAME_MAX: usize = 14;
+pub const _POSIX2_COLL_WEIGHTS_MAX: usize = 2;
+pub const _POSIX2_EXPR_NEST_MAX: usize = 32;
+pub const _POSIX2_LINE_MAX: usize = 2048;
+pub const _POSIX2_RE_DUP_MAX: usize = 255;