diff --git a/include/zephyr/posix/posix_features.h b/include/zephyr/posix/posix_features.h
index 099484555bc2..64d071afcff7 100644
--- a/include/zephyr/posix/posix_features.h
+++ b/include/zephyr/posix/posix_features.h
@@ -10,6 +10,7 @@
 
 #include <zephyr/autoconf.h>       /* CONFIG_* */
 #include <zephyr/sys/util_macro.h> /* COND_CODE_1() */
+#include <zephyr/kernel/thread_stack.h> /* K_KERNEL_STACK_LEN() */
 
 /*
  * POSIX Application Environment Profiles (AEP - IEEE Std 1003.13-2003)
@@ -279,6 +280,7 @@
 #define _POSIX_SIGQUEUE_MAX                 (32)
 #define _POSIX_SSIZE_MAX                    (32767)
 #define _POSIX_SS_REPL_MAX                  (4)
+#define _POSIX_STACK_MIN                    (K_KERNEL_STACK_LEN(0))
 #define _POSIX_STREAM_MAX                   (8)
 #define _POSIX_SYMLINK_MAX                  (255)
 #define _POSIX_SYMLOOP_MAX                  (8)
@@ -334,6 +336,7 @@
 #define PTHREAD_DESTRUCTOR_ITERATIONS _POSIX_THREAD_DESTRUCTOR_ITERATIONS
 #define PTHREAD_KEYS_MAX              _POSIX_THREAD_KEYS_MAX
 #define PTHREAD_THREADS_MAX           _POSIX_THREAD_THREADS_MAX
+#define PTHREAD_STACK_MIN             _POSIX_STACK_MIN
 #define RTSIG_MAX                     _POSIX_RTSIG_MAX
 #define SEM_NSEMS_MAX       _POSIX_SEM_NSEMS_MAX
 #define SEM_VALUE_MAX       _POSIX_SEM_VALUE_MAX
diff --git a/include/zephyr/posix/pthread.h b/include/zephyr/posix/pthread.h
index 685a8d9a9316..73464a77dd6e 100644
--- a/include/zephyr/posix/pthread.h
+++ b/include/zephyr/posix/pthread.h
@@ -54,9 +54,6 @@ extern "C" {
 /* Passed to pthread_once */
 #define PTHREAD_ONCE_INIT {0}
 
-/* The minimum allowable stack size */
-#define PTHREAD_STACK_MIN K_KERNEL_STACK_LEN(0)
-
 /**
  * @brief Declare a condition variable as initialized
  *
diff --git a/include/zephyr/posix/sys/sysconf.h b/include/zephyr/posix/sys/sysconf.h
index 67bf84bfb755..0508aca70d08 100644
--- a/include/zephyr/posix/sys/sysconf.h
+++ b/include/zephyr/posix/sys/sysconf.h
@@ -13,133 +13,166 @@
 extern "C" {
 #endif
 
-enum {
-	_SC_ADVISORY_INFO,
-	_SC_ASYNCHRONOUS_IO,
-	_SC_BARRIERS,
-	_SC_CLOCK_SELECTION,
-	_SC_CPUTIME,
-	_SC_FSYNC,
-	_SC_IPV6,
-	_SC_JOB_CONTROL,
-	_SC_MAPPED_FILES,
-	_SC_MEMLOCK,
-	_SC_MEMLOCK_RANGE,
-	_SC_MEMORY_PROTECTION,
-	_SC_MESSAGE_PASSING,
-	_SC_MONOTONIC_CLOCK,
-	_SC_PRIORITIZED_IO,
-	_SC_PRIORITY_SCHEDULING,
-	_SC_RAW_SOCKETS,
-	_SC_RE_DUP_MAX,
-	_SC_READER_WRITER_LOCKS,
-	_SC_REALTIME_SIGNALS,
-	_SC_REGEXP,
-	_SC_SAVED_IDS,
-	_SC_SEMAPHORES,
-	_SC_SHARED_MEMORY_OBJECTS,
-	_SC_SHELL,
-	_SC_SPAWN,
-	_SC_SPIN_LOCKS,
-	_SC_SPORADIC_SERVER,
-	_SC_SS_REPL_MAX,
-	_SC_SYNCHRONIZED_IO,
-	_SC_THREAD_ATTR_STACKADDR,
-	_SC_THREAD_ATTR_STACKSIZE,
-	_SC_THREAD_CPUTIME,
-	_SC_THREAD_PRIO_INHERIT,
-	_SC_THREAD_PRIO_PROTECT,
-	_SC_THREAD_PRIORITY_SCHEDULING,
-	_SC_THREAD_PROCESS_SHARED,
-	_SC_THREAD_ROBUST_PRIO_INHERIT,
-	_SC_THREAD_ROBUST_PRIO_PROTECT,
-	_SC_THREAD_SAFE_FUNCTIONS,
-	_SC_THREAD_SPORADIC_SERVER,
-	_SC_THREADS,
-	_SC_TIMEOUTS,
-	_SC_TIMERS,
-	_SC_TRACE,
-	_SC_TRACE_EVENT_FILTER,
-	_SC_TRACE_EVENT_NAME_MAX,
-	_SC_TRACE_INHERIT,
-	_SC_TRACE_LOG,
-	_SC_TRACE_NAME_MAX,
-	_SC_TRACE_SYS_MAX,
-	_SC_TRACE_USER_EVENT_MAX,
-	_SC_TYPED_MEMORY_OBJECTS,
-	_SC_VERSION,
-	_SC_V7_ILP32_OFF32,
-	_SC_V7_ILP32_OFFBIG,
-	_SC_V7_LP64_OFF64,
-	_SC_V7_LPBIG_OFFBIG,
-	_SC_V6_ILP32_OFF32,
-	_SC_V6_ILP32_OFFBIG,
-	_SC_V6_LP64_OFF64,
-	_SC_V6_LPBIG_OFFBIG,
-	_SC_BC_BASE_MAX,
-	_SC_BC_DIM_MAX,
-	_SC_BC_SCALE_MAX,
-	_SC_BC_STRING_MAX,
-	_SC_2_C_BIND,
-	_SC_2_C_DEV,
-	_SC_2_CHAR_TERM,
-	_SC_COLL_WEIGHTS_MAX,
-	_SC_DELAYTIMER_MAX,
-	_SC_EXPR_NEST_MAX,
-	_SC_2_FORT_DEV,
-	_SC_2_FORT_RUN,
-	_SC_LINE_MAX,
-	_SC_2_LOCALEDEF,
-	_SC_2_PBS,
-	_SC_2_PBS_ACCOUNTING,
-	_SC_2_PBS_CHECKPOINT,
-	_SC_2_PBS_LOCATE,
-	_SC_2_PBS_MESSAGE,
-	_SC_2_PBS_TRACK,
-	_SC_2_SW_DEV,
-	_SC_2_UPE,
-	_SC_2_VERSION,
-	_SC_XOPEN_CRYPT,
-	_SC_XOPEN_ENH_I18N,
-	_SC_XOPEN_REALTIME,
-	_SC_XOPEN_REALTIME_THREADS,
-	_SC_XOPEN_SHM,
-	_SC_XOPEN_STREAMS,
-	_SC_XOPEN_UNIX,
-	_SC_XOPEN_UUCP,
-	_SC_XOPEN_VERSION,
-	_SC_CLK_TCK,
-	_SC_GETGR_R_SIZE_MAX,
-	_SC_GETPW_R_SIZE_MAX,
-	_SC_AIO_LISTIO_MAX,
-	_SC_AIO_MAX,
-	_SC_AIO_PRIO_DELTA_MAX,
-	_SC_ARG_MAX,
-	_SC_ATEXIT_MAX,
-	_SC_CHILD_MAX,
-	_SC_HOST_NAME_MAX,
-	_SC_IOV_MAX,
-	_SC_LOGIN_NAME_MAX,
-	_SC_NGROUPS_MAX,
-	_SC_MQ_OPEN_MAX,
-	_SC_MQ_PRIO_MAX,
-	_SC_OPEN_MAX,
-	_SC_PAGE_SIZE,
-	_SC_PAGESIZE,
-	_SC_THREAD_DESTRUCTOR_ITERATIONS,
-	_SC_THREAD_KEYS_MAX,
-	_SC_THREAD_STACK_MIN,
-	_SC_THREAD_THREADS_MAX,
-	_SC_RTSIG_MAX,
-	_SC_SEM_NSEMS_MAX,
-	_SC_SEM_VALUE_MAX,
-	_SC_SIGQUEUE_MAX,
-	_SC_STREAM_MAX,
-	_SC_SYMLOOP_MAX,
-	_SC_TIMER_MAX,
-	_SC_TTY_NAME_MAX,
-	_SC_TZNAME_MAX,
-};
+/* Values assigned are intended to match the values assigned in newlib and picolib
+ * Even though the POSIX standard does not require specific values, this seems to be
+ * required for proper sysconf() operation when called from within newlib/picolib itself.
+ */
+#define _SC_ARG_MAX                      0
+#define _SC_CHILD_MAX                    1
+#define _SC_CLK_TCK                      2
+#define _SC_NGROUPS_MAX                  3
+#define _SC_OPEN_MAX                     4
+#define _SC_JOB_CONTROL                  5
+#define _SC_SAVED_IDS                    6
+#define _SC_VERSION                      7
+#define _SC_PAGESIZE                     8
+#define _SC_PAGE_SIZE                    _SC_PAGESIZE
+/* These are non-POSIX values we accidentally introduced in 2000 without
+ * guarding them.  Keeping them unguarded for backward compatibility.
+ */
+#define _SC_NPROCESSORS_CONF             9
+#define _SC_NPROCESSORS_ONLN             10
+#define _SC_PHYS_PAGES                   11
+#define _SC_AVPHYS_PAGES                 12
+/* End of non-POSIX values. */
+#define _SC_MQ_OPEN_MAX                  13
+#define _SC_MQ_PRIO_MAX                  14
+#define _SC_RTSIG_MAX                    15
+#define _SC_SEM_NSEMS_MAX                16
+#define _SC_SEM_VALUE_MAX                17
+#define _SC_SIGQUEUE_MAX                 18
+#define _SC_TIMER_MAX                    19
+#define _SC_TZNAME_MAX                   20
+#define _SC_ASYNCHRONOUS_IO              21
+#define _SC_FSYNC                        22
+#define _SC_MAPPED_FILES                 23
+#define _SC_MEMLOCK                      24
+#define _SC_MEMLOCK_RANGE                25
+#define _SC_MEMORY_PROTECTION            26
+#define _SC_MESSAGE_PASSING              27
+#define _SC_PRIORITIZED_IO               28
+#define _SC_REALTIME_SIGNALS             29
+#define _SC_SEMAPHORES                   30
+#define _SC_SHARED_MEMORY_OBJECTS        31
+#define _SC_SYNCHRONIZED_IO              32
+#define _SC_TIMERS                       33
+#define _SC_AIO_LISTIO_MAX               34
+#define _SC_AIO_MAX                      35
+#define _SC_AIO_PRIO_DELTA_MAX           36
+#define _SC_DELAYTIMER_MAX               37
+#define _SC_THREAD_KEYS_MAX              38
+#define _SC_THREAD_STACK_MIN             39
+#define _SC_THREAD_THREADS_MAX           40
+#define _SC_TTY_NAME_MAX                 41
+#define _SC_THREADS                      42
+#define _SC_THREAD_ATTR_STACKADDR        43
+#define _SC_THREAD_ATTR_STACKSIZE        44
+#define _SC_THREAD_PRIORITY_SCHEDULING   45
+#define _SC_THREAD_PRIO_INHERIT          46
+/* _SC_THREAD_PRIO_PROTECT was _SC_THREAD_PRIO_CEILING in early drafts */
+#define _SC_THREAD_PRIO_PROTECT          47
+#define _SC_THREAD_PRIO_CEILING          _SC_THREAD_PRIO_PROTECT
+#define _SC_THREAD_PROCESS_SHARED        48
+#define _SC_THREAD_SAFE_FUNCTIONS        49
+#define _SC_GETGR_R_SIZE_MAX             50
+#define _SC_GETPW_R_SIZE_MAX             51
+#define _SC_LOGIN_NAME_MAX               52
+#define _SC_THREAD_DESTRUCTOR_ITERATIONS 53
+#define _SC_ADVISORY_INFO                54
+#define _SC_ATEXIT_MAX                   55
+#define _SC_BARRIERS                     56
+#define _SC_BC_BASE_MAX                  57
+#define _SC_BC_DIM_MAX                   58
+#define _SC_BC_SCALE_MAX                 59
+#define _SC_BC_STRING_MAX                60
+#define _SC_CLOCK_SELECTION              61
+#define _SC_COLL_WEIGHTS_MAX             62
+#define _SC_CPUTIME                      63
+#define _SC_EXPR_NEST_MAX                64
+#define _SC_HOST_NAME_MAX                65
+#define _SC_IOV_MAX                      66
+#define _SC_IPV6                         67
+#define _SC_LINE_MAX                     68
+#define _SC_MONOTONIC_CLOCK              69
+#define _SC_RAW_SOCKETS                  70
+#define _SC_READER_WRITER_LOCKS          71
+#define _SC_REGEXP                       72
+#define _SC_RE_DUP_MAX                   73
+#define _SC_SHELL                        74
+#define _SC_SPAWN                        75
+#define _SC_SPIN_LOCKS                   76
+#define _SC_SPORADIC_SERVER              77
+#define _SC_SS_REPL_MAX                  78
+#define _SC_SYMLOOP_MAX                  79
+#define _SC_THREAD_CPUTIME               80
+#define _SC_THREAD_SPORADIC_SERVER       81
+#define _SC_TIMEOUTS                     82
+#define _SC_TRACE                        83
+#define _SC_TRACE_EVENT_FILTER           84
+#define _SC_TRACE_EVENT_NAME_MAX         85
+#define _SC_TRACE_INHERIT                86
+#define _SC_TRACE_LOG                    87
+#define _SC_TRACE_NAME_MAX               88
+#define _SC_TRACE_SYS_MAX                89
+#define _SC_TRACE_USER_EVENT_MAX         90
+#define _SC_TYPED_MEMORY_OBJECTS         91
+#define _SC_V7_ILP32_OFF32               92
+#define _SC_V6_ILP32_OFF32               _SC_V7_ILP32_OFF32
+#define _SC_XBS5_ILP32_OFF32             _SC_V7_ILP32_OFF32
+#define _SC_V7_ILP32_OFFBIG              93
+#define _SC_V6_ILP32_OFFBIG              _SC_V7_ILP32_OFFBIG
+#define _SC_XBS5_ILP32_OFFBIG            _SC_V7_ILP32_OFFBIG
+#define _SC_V7_LP64_OFF64                94
+#define _SC_V6_LP64_OFF64                _SC_V7_LP64_OFF64
+#define _SC_XBS5_LP64_OFF64              _SC_V7_LP64_OFF64
+#define _SC_V7_LPBIG_OFFBIG              95
+#define _SC_V6_LPBIG_OFFBIG              _SC_V7_LPBIG_OFFBIG
+#define _SC_XBS5_LPBIG_OFFBIG            _SC_V7_LPBIG_OFFBIG
+#define _SC_XOPEN_CRYPT                  96
+#define _SC_XOPEN_ENH_I18N               97
+#define _SC_XOPEN_LEGACY                 98
+#define _SC_XOPEN_REALTIME               99
+#define _SC_STREAM_MAX                   100
+#define _SC_PRIORITY_SCHEDULING          101
+#define _SC_XOPEN_REALTIME_THREADS       102
+#define _SC_XOPEN_SHM                    103
+#define _SC_XOPEN_STREAMS                104
+#define _SC_XOPEN_UNIX                   105
+#define _SC_XOPEN_VERSION                106
+#define _SC_2_CHAR_TERM                  107
+#define _SC_2_C_BIND                     108
+#define _SC_2_C_DEV                      109
+#define _SC_2_FORT_DEV                   110
+#define _SC_2_FORT_RUN                   111
+#define _SC_2_LOCALEDEF                  112
+#define _SC_2_PBS                        113
+#define _SC_2_PBS_ACCOUNTING             114
+#define _SC_2_PBS_CHECKPOINT             115
+#define _SC_2_PBS_LOCATE                 116
+#define _SC_2_PBS_MESSAGE                117
+#define _SC_2_PBS_TRACK                  118
+#define _SC_2_SW_DEV                     119
+#define _SC_2_UPE                        120
+#define _SC_2_VERSION                    121
+#define _SC_THREAD_ROBUST_PRIO_INHERIT   122
+#define _SC_THREAD_ROBUST_PRIO_PROTECT   123
+#define _SC_XOPEN_UUCP                   124
+#define _SC_LEVEL1_ICACHE_SIZE           125
+#define _SC_LEVEL1_ICACHE_ASSOC          126
+#define _SC_LEVEL1_ICACHE_LINESIZE       127
+#define _SC_LEVEL1_DCACHE_SIZE           128
+#define _SC_LEVEL1_DCACHE_ASSOC          129
+#define _SC_LEVEL1_DCACHE_LINESIZE       130
+#define _SC_LEVEL2_CACHE_SIZE            131
+#define _SC_LEVEL2_CACHE_ASSOC           132
+#define _SC_LEVEL2_CACHE_LINESIZE        133
+#define _SC_LEVEL3_CACHE_SIZE            134
+#define _SC_LEVEL3_CACHE_ASSOC           135
+#define _SC_LEVEL3_CACHE_LINESIZE        136
+#define _SC_LEVEL4_CACHE_SIZE            137
+#define _SC_LEVEL4_CACHE_ASSOC           138
+#define _SC_LEVEL4_CACHE_LINESIZE        139
+#define _SC_POSIX_26_VERSION             140
 
 #define __z_posix_sysconf_SC_ADVISORY_INFO (-1L)
 #define __z_posix_sysconf_SC_ASYNCHRONOUS_IO                                                       \
@@ -295,10 +328,6 @@ enum {
 #define __z_posix_sysconf_SC_TTY_NAME_MAX                 TTY_NAME_MAX
 #define __z_posix_sysconf_SC_TZNAME_MAX                   TZNAME_MAX
 
-#ifdef CONFIG_POSIX_SYSCONF_IMPL_MACRO
-#define sysconf(x) (long)CONCAT(__z_posix_sysconf, x)
-#endif
-
 #ifdef __cplusplus
 }
 #endif
diff --git a/include/zephyr/posix/unistd.h b/include/zephyr/posix/unistd.h
index b7ac069bdc5e..76ab340cf47d 100644
--- a/include/zephyr/posix/unistd.h
+++ b/include/zephyr/posix/unistd.h
@@ -11,11 +11,6 @@
 #ifdef CONFIG_POSIX_API
 #include <zephyr/fs/fs.h>
 #endif
-#ifdef CONFIG_NETWORKING
-/* For zsock_gethostname() */
-#include <zephyr/net/socket.h>
-#include <zephyr/net/hostname.h>
-#endif
 #include <zephyr/posix/sys/confstr.h>
 #include <zephyr/posix/sys/stat.h>
 #include <zephyr/posix/sys/sysconf.h>
@@ -49,10 +44,7 @@ int rmdir(const char *path);
 FUNC_NORETURN void _exit(int status);
 
 #ifdef CONFIG_NETWORKING
-static inline int gethostname(char *buf, size_t len)
-{
-	return zsock_gethostname(buf, len);
-}
+int gethostname(char *buf, size_t len);
 #endif /* CONFIG_NETWORKING */
 
 #endif /* CONFIG_POSIX_API */
@@ -72,7 +64,8 @@ size_t confstr(int name, char *buf, size_t len);
 #endif
 
 #ifdef CONFIG_POSIX_SYSCONF_IMPL_MACRO
-#define sysconf(x) (long)CONCAT(__z_posix_sysconf, x)
+/* Can't use CONCAT(), must concat directly to prevent expansion of 'x' */
+#define sysconf(x) (long)__z_posix_sysconf##x
 #else
 long sysconf(int opt);
 #endif /* CONFIG_POSIX_SYSCONF_IMPL_FULL */
diff --git a/lib/posix/options/device_io.c b/lib/posix/options/device_io.c
index 6fea22d01545..83c180fa9d20 100644
--- a/lib/posix/options/device_io.c
+++ b/lib/posix/options/device_io.c
@@ -99,7 +99,7 @@ int pselect(int nfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds,
 	return zvfs_select(nfds, readfds, writefds, exceptfds, timeout, sigmask);
 }
 
-ssize_t pwrite(int fd, void *buf, size_t count, off_t offset)
+ssize_t pwrite(int fd, const void *buf, size_t count, off_t offset)
 {
 	size_t off = (size_t)offset;
 
diff --git a/lib/posix/options/net.c b/lib/posix/options/net.c
index 84e4001a9b40..f799adaffd4f 100644
--- a/lib/posix/options/net.c
+++ b/lib/posix/options/net.c
@@ -10,6 +10,7 @@
 #include <stdlib.h>
 
 #include <zephyr/net/net_if.h>
+#include <zephyr/net/socket.h>
 #include <zephyr/posix/arpa/inet.h>
 #include <zephyr/posix/netinet/in.h>
 #include <zephyr/posix/net/if.h>
@@ -216,6 +217,11 @@ struct hostent *gethostent(void)
 	return NULL;
 }
 
+int gethostname(char *buf, size_t len)
+{
+	return zsock_gethostname(buf, len);
+}
+
 int getnameinfo(const struct sockaddr *addr, socklen_t addrlen, char *host, socklen_t hostlen,
 		char *serv, socklen_t servlen, int flags)
 {
diff --git a/lib/posix/options/sysconf.c b/lib/posix/options/sysconf.c
index 881d83ceebf6..a854fa6b48f7 100644
--- a/lib/posix/options/sysconf.c
+++ b/lib/posix/options/sysconf.c
@@ -6,13 +6,12 @@
 
 #undef _POSIX_C_SOURCE
 #define _POSIX_C_SOURCE 200809L
-#include <zephyr/posix/pthread.h>
 #include <zephyr/posix/sys/sysconf.h>
 #include <zephyr/posix/unistd.h>
 
 #ifdef CONFIG_POSIX_SYSCONF_IMPL_FULL
-
-#define z_sysconf(x) (long)CONCAT(__z_posix_sysconf, x)
+/* Can't use CONCAT(), must concat directly to prevent expansion of 'x' */
+#define z_sysconf(x) (long)__z_posix_sysconf##x
 
 long sysconf(int x)
 {
@@ -125,21 +124,17 @@ long sysconf(int x)
 		return z_sysconf(_SC_TYPED_MEMORY_OBJECTS);
 	case _SC_VERSION:
 		return z_sysconf(_SC_VERSION);
-	case _SC_V6_ILP32_OFF32:
-		return z_sysconf(_SC_V6_ILP32_OFF32);
-	case _SC_V6_ILP32_OFFBIG:
-		return z_sysconf(_SC_V6_ILP32_OFFBIG);
-	case _SC_V6_LP64_OFF64:
-		return z_sysconf(_SC_V6_LP64_OFF64);
-	case _SC_V6_LPBIG_OFFBIG:
-		return z_sysconf(_SC_V6_LPBIG_OFFBIG);
 	case _SC_V7_ILP32_OFF32:
+		/* case _SC_V6_ILP32_OFF32 */
 		return z_sysconf(_SC_V7_ILP32_OFF32);
 	case _SC_V7_ILP32_OFFBIG:
+		/* case _SC_V6_ILP32_OFFBIG */
 		return z_sysconf(_SC_V7_ILP32_OFFBIG);
 	case _SC_V7_LP64_OFF64:
+		/* case _SC_V6_LP64_OFF64 */
 		return z_sysconf(_SC_V7_LP64_OFF64);
 	case _SC_V7_LPBIG_OFFBIG:
+		/* case _SC_V6_LPBIG_OFFBIG */
 		return z_sysconf(_SC_V7_LPBIG_OFFBIG);
 	case _SC_BC_BASE_MAX:
 		return z_sysconf(_SC_BC_BASE_MAX);
@@ -237,10 +232,9 @@ long sysconf(int x)
 		return z_sysconf(_SC_MQ_PRIO_MAX);
 	case _SC_OPEN_MAX:
 		return z_sysconf(_SC_OPEN_MAX);
-	case _SC_PAGE_SIZE:
-		return z_sysconf(_SC_PAGE_SIZE);
 	case _SC_PAGESIZE:
-		return z_sysconf(_SC_PAGESIZE);
+		/* case _SC_PAGE_SIZE */
+		return z_sysconf(_SC_PAGE_SIZE);
 	case _SC_THREAD_DESTRUCTOR_ITERATIONS:
 		return z_sysconf(_SC_THREAD_DESTRUCTOR_ITERATIONS);
 	case _SC_THREAD_KEYS_MAX: